What to do? 350 engine budget build! $1500 - $2000 Max

All good points. A 455/400 trans swap with a rering and bearing , cam , lifters, springs and timing set with a Quadrajet can cost more then a cam lifter, spring and timing set ,with a Quadrajet and convertor with .050-.060 shaved off heads of the 350 . And the added expense of frame pads and mounts, front springs , fan shroud and possibly a bigger radiator,shortened driveshaft.modifed exhaust to fit 455. And compared to a reringed 71-74 engine power from the 455 isn't A whole lot more power, more torque due to size.Both being above 250 hp and doubtfully clearing 300. And he won't know what his actual compression is until he pulls heads and measures specs of the 350. Much less work and expense , add a 350 trans and go. Atleast if he does go 455 later the 350 will be impressive enough for anyone looking for a 350 with similar 70 GS 350 power which will be worth a few extra $$ at sale. Everyone always claims to have a cam in the engine for sale but a comp 260 or 268 in a 7.7 compression engine has the makings of a boring slug.
Just my thoughts.
If anything do the 350 for now and build a 600 hp 470 over time.

 

Yeah, that's why I didn't recommend just re-ringing whatever pistons were in the core he found, you summed it up there about the low compression '74 to '76 455s would be a slug but just with a bit more torque and cubes than the 350 he has now.

Me personally would never buy a "running" engine and swap it in for more performance unless it was an engine I previously built, and know what's in it and its history. Other than that I would at the minimum disassemble, clean and then re-assemble the engine making sure it goes back together to my standard before I went through all the work to remove a perfectly good running engine to install another one!

Clean, hone, freeze plugs and cam bearing installed for block work about $350

The compression distance correcting pistons and ring kit(AutoTec piston and ring kit) to dial in compression ratio, $649

Crank polish $75

Cost of cam and lifters around a couple hundred$?Say $200

valve job around $200

Bearings, around $200

Balancing, about $200

Used al. intake maybe $200 to $400

engine gasket kit, say $200

ARP rod bolts, not sure so I'll write $150

Install new rod bolts and recon 8 rods, $80

Rebuilt Q-jet that came with 455, not sure but I think is around $300

Re-use as many parts as possible, with a grand total not including maintenance and tune up parts and supplies of; right at $2900 plus or minus a few hundred $.

This is if he recoups at lease as much $$ by selling the sbb 350 as the BBB 455 core cost? This route would just about guaranty that the OP would be happy with the results after installation with an engine that could even be upgraded in the future if even more HP is wanted. The above is a recipe for a solid 430 HP minimum with around 500 ft lbs of torque on tap to boot. If the OP is energetic and ambitious enough to attempt some home port work and is successful he could up the HP another 20 to 50 HP and torque depending how good he does. Or just run the heads with the new valve job and save up for a set of Edelbrock to up the output an extra 40 to 60 depending on cam choice.

Getting the same HP numbers out of the sbb is possible but would be much more costly to achieve for a novice engine builder, plus it would need to be much more planned out to function with the rest of the driveline to work as well as the BBB power.

There is another alternative, isn't Mark Burton making the sbb twin turbo kits again? Not sure how much those kits cost, but that would be a bolt on performance "pill" to up the HP of what he has in the car now. I think Sean got 460 RWHP with a basically stock sbb 350 IIRC before he lost #3 cylinder from head gasket failure with that kit.

Fun stuff, GL.




Derek

 

Just an FYI, the low comp 455 will have more than just a 'bit' more torque...

Don't sell 105 more cubes short.

Remember the net figures are way different than the gross figures, and a fair translation shows the weakest 455 to have around 275 hp and 460 ft. lbs.

While the hp isn't impressive, the torque certainly is, and would easily be +100 ft. lbs. more than the low comp 350 it would be replacing, with 25-30 more hp to boot.

If you can hear the engine running in the car and it doesn't smoke or knock and the oil looks good, why tear it apart unless you just wanted to say you had your hands up its skirt?

Even so, if it bothered ya that much, sure, tear it down, rehone, rering, put new bearings in and a small performance cam and have even MORE power with little money spent.

It won't matter if the oiling isn't perfect for a 7,000 RPM screamer, it'll probably never see over 5,000 anyway or for very long. The block core and lifter bore shift won't matter for a mild engine either.

These engines are very forgiving when rebuilding them with a basic function in mind, much like the factory did.

You can't help but make power with 455 cubes. You don't even have to try, it's already there! lol

 

Anyone who suggests an LS engine swap should be banned from the board as they just don't get it. There are way more Chevy boards, go there. LOL

Go get a copy of Hot Rod Magazine and watch Overhaulin for more boring LS action.

 

read the entire post carefully Gary as you missed skipped several points.
A 350 with true measured 9 to 1 compression,proper cam,TA intake, tuning, and convertor can produce results near that range. As 68 350-4 rated 280 hp,345 lbs vs the very very optimistic 460 lbs on 8.5 compression ? (Sorry but the 1970 stage 1 is only worth 60 more lbs?)
I don't disagree that it will make more power if done well, but there is much more work to do with a 455 swap unless it's a drop in engine. And chances are your going to want a cam swap too. And a carb build

 

So I think after all this I am more confused than ever lol. But seriously I thank you all for your messages and I think it's time to drop in the 455 with the th400 transmission. Now I just have to find both. I am thinking 455 with a super mild rebuild just valves and refreshing no head work and a qjet. That should net me 300 horses. It's a convertible That's about as fast as I need to go anyhow.

 

And that's the problem with coming on V8buick asking for opinions....it will leave you confused. Just go with your gut and expect problems.

Now having said that.....if it were me, I would spend the 1500-2000 on a basic rebuild with hi-comp pistons and a good cam. Then you can upgrade from there know that you have a good foundation to work with, ie headers, intake, carb. The key is to HAVE A PLAN BEFORE YOU START SPENDING $$$$. Otherwise you will find yourself running in circles.

 

Not quite sure what's being said here, but there is no way a mild 350 even compares to a mild 455 in the way it shoves the vehicle around.
It doesn't matter what the little blip at the shift point is for hp...there's so much more torque from an equivalent 455 from idle all the way to the shift.

 

A 455 with about 9.5 compression, cleanup port on heads with edelbrock intake, shorty headers proper built Quadrajet and a 284-88 TA cam will net about 420 + hp and 500 lbs torque easily. Then you will need a 2500 convertor and 3.42 gears. I have basically that in a 430 in my first convertible with a 1000 cfm Holley terminator efi . 12 second car. My second convertible has a 70 SP 350 with a TA 310 cam TA intake , Quadrajet,a lot of porting , 3000 stall and 3.73 gears. Not as fast but still fun. (Blue one 430,orange one 350)

 

It is easy, you buy the 455 put on some headers and your carb, Which will be a Q-jet anyways, Then once it is in there with your 400 trans, btw, the 350 trans will hold up to a 455, watched a guy do it at the track all the time and it was yanking the wheels. Then later on when you get tired of all that power then you start to do some of the things like change cam, get the heads done, maybe go as far as tearing the rest of it apart and do pistons an all that crap.

I stuffed a cam in my stock 350 shift kit in trans, headers, then I got the gears and when I had more money. Then when I got more money I took it out and everything redone. Have fun with the damn thing first then decide what to do. Don't listen to all the crap being told to do you don;t need to. Drop the 455 in there and go burn some rubber, it will have more power than you think, and if not then upgrade, Then you go to the 455 side of town, on here. Do the cheap easy stuff first, headers, dual exhaust, carb rebuilt, personally I would get a Holley 750 double pumper myself it will serve both engines, then get a intake, then get the gears. At this point you will know how much more power you need then decide on the heads, TQ convertor, compression and all that other jazz that takes the most money to do. K.I.S.

 

You are new to this aren't you. Anyway, if 300 HP is all you're after with your convertible then a BBB would be to much work and $$ to swap in if that is all the power you're after.

If that 350 in the car now has been previously a newer rebuild then I would say it was done with off the shelf "stock" replacement pats like "stock" replacement pistons or "builder" pistons that are the so called factory replacement pistons. If so then if the deck wasn't milled .020" under the blueprint dimension of 10.188"(which is usually an extra at least +.030" already from the factory!) then that piston is another .020" in the hole further lowering the compression ratio. Now to save $$ when this was re-built I will hazard to guess that the Fel-Pro head gaskets were used because they skipped machining the deck, so the pistons are another .020" in the hole because those gaskets are .020" thicker than the steel shim factory style head gaskets. To save even more $$ because "who cares its only a 350" they used the cheaper "8.5:1" advertised pistons because those were the cheapest ones that are sold. But without doing any measuring and those "stock" replacement pistons in there the compression I am thinking is closer to 7:1 compression than 8.5:1 because of the above mentioned extra thicknesses that weren't blueprinted to make the 8.5:1 advertised pistons an actual 8.5:1 compression ratio.

Bare with me here because if all you want is 300 HP then the 350 you have in the car will hit that number better because the small block will be more efficient at that power range than an low compression 455 would be. A crappy low compression 455 in your car would be like flushing an old style toilet with the 6 gallon tank on it every mile you drive your car with if you're lucky 10 mpg! IMO that extra torque isn't worth that price when at that power level even without overdrive a sbb 350 can get close to twice the mpg! Low compression '74 to '76 455 with 460 lb ft, HAH! NOT! 360 net doesn't = 460 gross!! And compression was rated to be 8.5:1 for '74 but only 7.9:1 for '75 and '76, so probably more like 7.5:1 for those 2 years which really killed the torque output of those year 455s with a listed 345 lb ft net which would only gross about 30 more lb ft at the most for the gross torque, a far cry from 460.

If your car is a sweet ride then it deserves better than a junkyard core, that is exactly what most of the "running" used antique engines that are for sale out there are being that 1976 was the last year they built a car with a BBB 455 in it. That car is driven to be enjoyed, not a daily driver that you're just trying to get running so you can make it back to work the next day so who cares what engine is installed in it kind of BS! Do it right the first time and you will be many many $$$ ahead than installing some one else's junkyard core in your car! That's just my honest opinion because I'm getting to old to do all the work to take an engine out, then install another one for it to only last a couple miles. There are threads here on v8buick that guys did just that, bought a "used running" 455, swapped it in only to have it fail a few miles later.

Now back to the power you want, the 300 HP, the sbb you have can be made to make that without even removing the engine from the car! Just listen to what Andy wrote on the first page and shave heads .060", have intake side milled .030" each head's intake surface, use steel shim head gaskets get .080" shorter pushrods and a Crower level 2 cam and a Stage 1 intake if you can find a deal on a used one or just use the factory cast iron 4bbl one with a Q-jet from the mentioned Q-jet builders here on v8. This is all that you need to do at this time to get the engine to that power range, probably less than $1,000. Next step is a TH350 with a converter matched to the cam, and if that isn't enough, a gear swap to get you how you want the off the line acceleration to be. So about $1,000 for rebuilt trans and new converter and another $500 for the gear change and you'll be where you want to be.

Swapping in a 455 will be opening a can of worms with your level of experience with all the extras needed to make that swap right. Perhaps in a couple of years of being an old car owner and learning how to work on the car those years you own it you'll be ready for an undertaking such as the sbb 350 to BBB 455 swap.

You'll need BBB frame pads and BBB motor mounts for your specific car as well as a BBB shroud and BBB front suspension springs among other things needed to do that swap. It doesn't seem you're ready for that type of mechanical work, unlike guys suggesting putting in a "used" engine(which is more often than not nothing more than a junkyard core IMHO), those guys probably have done an engine swap or 2 and not a big deal for them to R&R the engine another time because their "deal" failed. Or perhaps they are thinking of the 1980s when those engines were more plentiful as well as being 30 years newer than they are today! o No:

Its your car so its ultimately your decision, but sticking with an in car build would be your best bet at your experience level IMHO. GL



Derek

 

With any modest budget, one would be somewhat reliant on the condition of the engine being suspect and limited by skills.

 

Semantics and net-gross translations aside, you can't dispute 105 more cubes having more torque, no matter how badly you want to whittle it down. Trying to claim a low comp 455 barely scrapes by with scarcely more torque than a 350 is so exaggerated I can't even start to politely comment on it. I've compared a high comp 350 (not a low comp 350, which wouldn't even compare) to a low comp 455 side-by-side in a direct swap over with nothing else changed. The torque difference was huge.

I should have refrained from posting actual numbers as I should have known better than to think it wouldn't be nitpicked in at attempt to discredit anything I say.

A good running big block that lived all this time in the car it came out of isn't going to magically fail the moment you put it into another car. The engine he has in his car now came out of a newer low comp-era car, and it's running good. Why hasn't it failed?

I can understand wanting to keep the 350 in there, I love them too. I'd also love to see others here do business with other board members to make money off their trade. What I don't love is seeing this being pushed despite the best interests of the OP. Obfuscating the facts or flooding with too many details can distract and confuse. I'm guilty of this same thing, but I'm trying to learn how to keep things simpler, especially for novice or younger enthusiasts.

With limited funds comes limited options if your goal is getting the most power for your money.

 

Bottom line is the 455 will beat any 350 no matter what year it is. The 1970 350 stock with its supposedly 315 hp will not beat any 74 455 in the 1/4 period. I was around back then I know. The people that have good a running 350 are not on here or make very few comments.

But don't get me wrong, my 350 runs. and if you have a 455 that runs I will squirt a 75 shot in to match you. Watch the U-Tube in my sig to see.

Underdog has a great running pretty much stock 350 I would follow his recipe if you want to stay on the near stock side, pm the guy I would.

 

This why I am a firm believer in gearing. You would be amazed at how much performance can be gained by it as opposed to just making more horsepower. A 2004R has a 1st gear of 2.74 and an OD ratio of .67. Even a stock GN D5 converter stalls at 2,200rpm. Couple that up with a 4.10 gear and you're out of the hole like a jackrabbit. On the highway, in overdrive your final ratio will be 2.74. And you'll have lockup so that eliminates converter slippage. It doesn't get any better than that when trying to move a small block of any brand.

 

The torque multiplication is what's important.
A 300tq engine going to the 2.74 would be equiv to 465tq (from the 1.76), or just like picking up an extra gear down low.
A 400tq engine going to the 2.52 would be equiv to 560tq (from the 1.76). No match for cubes, assuming both engines are in good shape.
An engine in good shape should be capable of 1 lb per cube of tq. at 8.5-1, tuning required and basic breathing problems handled.

 

Gary,

Actually, you were right on the money with your torque number..

I recently built a completely stock 73 455 "smog motor".. Of course, this is not a half baked deal, it's completely machined and rebuilt. The only additions are Stage 1 stainless valves from TA, along with the correct chamber and throat cuts to install them just like the factory did. Absolutely no porting. I also installed a 218* cam (straight pattern) because my experience has taught me that even these low compression motors tend to detonate with the tiny factory camshaft.

I was very surprised at the results. Power is very near that of a 70 Stage 1 engine, in stock trim. That 510 torque numbers is something I have never actually seen on a modern dyno. 465 is about what we see, at best on a truly stock 70 engine. I had a conversation with Dennis Manner about this not too long ago, and he related to me that they were allowed to block the exhaust gas off from intake heat riser, as well as to correct their numbers to 60* dry air.. that correction is more substantial that the industry standard now, with is 72* dry air..

Here is a rundown of the engine:

Stock 73 block, heads with STG 1 conversion, untouched intake, exhaust manifolds, stock rebuilt and modified timing cover, stock oil pan, 5/8 pickup.

Cast replacement pistons, reconditioned stock rods with bolts, reman damper and flexplate, fresh ground crank. Standard clearances (.002 to .0025 rods and and mains.)

Stock replacement timing chain, Comp 268H cam, good check ball hyd lifters, autoline production reman 73 455 Q-jet carb, reman points distributor.

Measured 8.3-1 static compression ratio.

Here are the surprising results,





Compare that to a 9-1 70 455, with a touch of head porting, and a TA 212cam and performer intake 750 Qjet



All this being said, I think the OP is not in the neighborhood of the cash required to build and swap in a 455, so I tend to agree with those that advocate a fluffing of the 350, until funds become available for something more serious.

JW

 

With 460 ft lbs of TQ at 3000 rpm that is going to beat any 350 out there. It would probably give me a run for the money and I am modified.
That car will probably run in the 13's somewhere maybe more. Shift at 5 grand and it will live forever. Put a t400 auto behind it with a 355 or 364 gear or 373-410 gear with the 4 speed 2004r and no one will touch you on the street and will smoke the tires until the next rubber plant grows.

But I like my 350 so you can put some parts on it and have fun until you get more money to do the rest. I put in a Comp Cam 268 in back in 1983 and had a Kenne Bell book and it was all a pipe dream that I thought would never happen and in 94 I got the 350 built with my TA510 cam. 390 hp at 6 grand.

With the new parts for the 350 there is no reason to not have a lot of power with a 350 just got to plan it out.

 

After rethinking this subject a bit, I've decided to post some more 'pros and cons' about the 350 vs the 455 in this situation.

Yes, a low comp 455 will be faster than a high comp 350, depending on gearing and work done to each.

However...

Good running 455's ready for a direct swap-over aren't exactly growing on trees anymore, so a rebuild will be likely on it even if you find a good one that's been sitting around for a while, so there goes the 'less involved' aspect of building the 350 that already exists in his car.

The torque number I gave for the low comp 455 was simply a math translation from net to gross, which can be off a bit. It's unlikely a stock '75 455 is producing an actual 460 ft. lbs., even though Jim shows his rebuilt one does...but to be fair, it has a cam, better compression (slightly), and larger valves--unlike the untouched factory engine that rolled off the assembly line in 1975.

A more realistic number for a 1975 455 would probably be closer to 420-430 ft. lbs....which is still much better than the 330-340 ft. lbs. you'd see on a stock smogger 350 (again, 'guestimation' numbers, so don't take them too literal).

My viewpoint on suggesting the low comp 455 was that he could still use regular gasoline, and if a good running one was found, could simply swap it over with relatively minimal involvement inside the engine itself, while using his existing gearing. The extra power would be easily felt and the car would perform better overall vs what's in there now.

Finding a good, running, untouched 455 is easier said than done.

Perhaps a revisit to the old 'just rebuild the 350' mindset deserves another look.

Unless you're familiar with a lot of torque in a lighter car, you can get into trouble or get hurt if you're not careful with it.

For a basic cruiser that gets decent gas mileage and has some spring to its step, the 350 is a fine choice.

To keep costs down, I'd leave the rear end alone, and swap in a TH350 (which are a dime a dozen and are pretty tough). A basic rebuild with a mild shift kit should do nicely. Be mindful that the detent is cable controlled, so may want to omit it and just downshift manually (preference here, which is what I'd do). It will also be a direct bolt over swap from the ST300. Driveshaft will fit, and uses the same transmission crossmember and position the ST300 uses. It is literally a direct bolt in replacement. Easy enough.

You can go back through the 350 if you want, raise the compression with higher comp cast pistons--but this is where it gets tricky. We don't know if the Federal Mogul (Speed Pro) replacement pistons are any good. They're made in India now, and the quality is under question. The manufacturer assures me (and others) that they're fine, but that's to be expected. I'm not sure if there's some kind of sonic testing that could be done to make sure the silicon and other defects could be detected this way to ensure the pistons are good to use.

But then again, the low comp pistons aren't in a better position either. The only way around this would be to get the forged offerings, which are excellent, but are more expensive.

Unless of course, the pistons in it now are the original factory offerings, in which case are fine to use. Won't know until the engine is torn down.

Anyway, I'm prattling and I don't want to bore or confuse.

You could keep the engine as is now and do a cam swap to one that has an earlier valve closing point for better dynamic compression. What this means is the engine in there now will have better torque and performance than what it is now, and couple this with the trans swap, your costs will be pretty low and performance WILL go up.

But would you be happy with it? Do you want to burn rubber, or do you just want an edge over what's in the car now?