Putting an abomination in my Buick? maybe?

Discussion in 'Small Block Tech' started by 71Skylark1384, Jan 10, 2016.

  1. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    let me give you a break down. Last year I purchased a chevy 305 vortec from a buddy. Having a friend of my building it up for me. Reason was, I needed a cheap engine that I can find parts for easily. Started off just doing a stock rebuild but then put some performance parts in it. Fast forward till now. The block was just sitting at my buddies place and I have not yet put it in the Buick. Come Christmas morning, I opened a present from my dad. In it was a Guide to Buick performance engines. Started reading this and it kindle my flame back towards the 350.

    So that being said. I am planning on rebuilding this beautiful Buick 350. I learn more and more about the car and engine each time I work on it. Its like a never ending story book, learn something new every day. I've matched the numbers and the engine is the original that came with the car. Guy I bought the car from was trying to make it in a street drag car. I have no idea what he did to it other than he had put a bigger cam in it and edelbrock 4 barrel carb (650 i think) It has a Poston S-divider intake manifold and some sort of competition headers. Guy had taken the AC compressor out also. Oh and the transmission is a TH400. With this being said....
    I've been looking online for a rebuild kit. I would like to rebuild the engine close to a 10:1 compression ratio. Kits I've seen range from $400-$850
    Been doing research on the Poston intake manifold. Most what I've read does not speak favorable towards the Poston intake. Maybe down the road I'll change it. But with this intake manifold can I achieve a 10:1 cr? I also know that the heads are a factor in this. i am planning on rebuilding them too.

    I'm a newb at this so forgive me if this may sound far fetch. Throw your knowledge at me and/or suggestions thanks :TU:
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The intake manifold has nothing to do with the compression ratio. The Poston intake has never been anyone's favorite. I have heard it needs a spacer to run it's best. The original Q-jet fit to the engine was a 750, so a 650 Edelbrock carburetor is not the best choice. I suggest you read through this thread,


    There will be some aluminum heads for the SBB soon. That will be a real game changer.
  3. sriley531

    sriley531 M.M.O.G.

    Edit: Larry beat me to the draw, so some of this is a repeat! Sorry!

    Your intake has nothing to do with compression ratio. CR's are primarily determined by the combustion chamber volume of the head, how far into the cylinder the piston is at TDC, and when the cam is opening and closing the valves. So be aware of any parts (pistons for example) that say "10:1 CR". Yes, they can achieve that, but only with a certain combination of supporting parts. Even your head gasket selection makes a difference. Decking the block is a common procedure to help achieve a desired CR with certain pistons, so you may need to look into that. Also, do some research and read up on the differences between static CR and dynamic CR. These are useful tools is getting the correct combination.

    As far as that particular intake goes, I've heard mixed things but can't say I've ever dealt with one. I do have some experience playing with a nicely warmed over buick 350 that used a ported TA stage 1 and it was a great engine, but many say other than the weight advantage little performance is gained by the intake alone. Again, you'll hear lots of differing opinions.

    One thing I want to stress is before learning the ins and outs of putting together a good combination of parts (and solid engine performance is ALL about having a combo that works well together), determine how you plan to use the car and what you want out of it. A pleasant driver with a bit more go? A classic with as good a mpg as possible? An all out go fast at all costs shifting at 7k racer? There are trade offs that will have to be made for all of the above. Also, depending on what you choose there, it may warrant changes in the rest of your driveline (most commonly torque converters and rear gear ratio).

    Alot to wrap your head around, I know! But with the proper knowledge and approach, these sbb's can really be a cool engine. Especially with the potential of finally getting aluminum heads for these engines. Could really be a game changer.
  4. pbr400

    pbr400 68GS400

    So the 'abomination' title and 305 story have nothing to do with each other? At first it sounds like they do and you may lose a few readers; when they see Chevy 305 they're gone. Now, as to your questions--
    First, you need to determine how healthy your 350 is. Does it run now? An otherwise healthy engine can run very poorly and seem fubar if it's timed wrong, has vacuum leaks, wrong or bad carb, etc. Does it make knocking noises when it runs? Does it have good compression? If it's healthy it makes no sense to tear it apart just to raise compression. There's several 350 gurus on V8 (look in 'small block tech') who can guide you, but in general I'd say unless it has a crazy big cam now, if it's healthy then tune it, curve the distributor, find a good Quadrajet carb (there's thread after thread about how wrong the Eddy carbs are and how right a Q jet can be) and assemble what you have. Oh, and intakes have no effect on compression. If you've never driven a well tuned healthy 350 car set up right, you may be surprised (and surprise others) with how lively they are. Go to small block tech and read a lot, then ask for help.
    Good luck!
  5. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    The title was towards the 305 and my very close attempt of putting a chevy engine in a buick. From what I've read when I first started that project, alot of buick guys are against it. I don't blame them, keep it buick 100%. But enough of the title.

    I've had no major issues with the 350. No smoke, not knocking or ticking or tapping. It actually runs really good right now and sounds mean. What prompted me to rebuild it was trying to get the timing correct. It came to replacing the distributor drive gear. When I did this I looked inside the block and saw the gears on the cam. It was in pretty bad shape, and even started to chip away the brand new drive gear on the distributor. Also I did replace the gasket under the intake manifold and replaced the water pump. This engine runs great but I do see some frankinstien mods on it. Like a C-clamp replacing a bolt to hold part of the headers on. and the bolts for the water pump are not all there and are makeshift.

    I want to make it a car where I can take it out to the strip or a car show eventually. Burn some rubber and have some performance other than stock. Its garage kept and been so since I purchased it over 10 years ago.

    That build up thread is an excellent read and its dummy proof. Which works for me. I'm not here for a re-post of different threads just a direction toward my scenario and of course any tips.
  6. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    What is your budget for this project? What is your time allowance to get it done?

    I would suggest if the engine runs good now that you find a rebuildable sbb 350 core to start with so you can take your time money wise so you can build something you won't be disappointed in.

    I would recommend if you want a naturally aspirated 10:1 street/strip sbb 350 to add a few extra cubes by over boring and stroking. The nascar takeout rods on eBay still have a whole lot of life in them for a street/strip sbb 370 to 390 cid engine. Compared to running in an nascar engine @ a sustained 9 or 10 thousand RPM, being in a sbb street/strip engine that sees 7,500 RPM once and a while would be like they're out to pasture still alive but taking it easy now, even with a boosted application.

    If you take your time on this build and decide to do a stroker you can also save up your cash for a set of the new TA sbb 350 heads that are supposed to be coming out soon. A custom roller cam would help maximize the combo as well. The new heads will be setup to use sbc stud mounted rockers to save a bit of expense but will also be able to bolt on a stock rockers or the TA shaft roller rockers.

    I sonic tested a sbb 350 block that is thick enough to take to a 4.00" bore, I would recommend that you have whichever block you decide to use to have it sonic tested to see how far the bore can be taken if you decide on doing a stroker.(should only cost around $100 and would be well worth the cost to know how your block will handle a performance build, it may not be worth putting anymore $$ into or it could be thick enough to handle a 4.00" bore? You won't know without having the block sonic tested or X-rayed, I think X-raying could be more expensive though, not sure never dealt with a shop that does that)

    With a 4.00" bore and the crank stroked to 3.990" your little sbb 350 would now be a sbb 401!!! You would need a set of nascar take out rods with the 1.850" rod journal size to have a virgin never been re-ground sbb 350 crank taken to a 3.990" stroke. AutoTec makes sbb 4032 forged pistons that are customizable for the same advertised cost if you want to go the N/A 10:1 stroker route.

    This should be enough for now, if you're interested in a sbb stroker let me know by posting your interest in this thread and I will help as much as I can. GL

  7. techg8

    techg8 The BS GS

    Check out falcon global on ebay, they usually have reasonably priced engine overhaul packages. I know I've seen ones with hi comp pistons for buick 350 too, from them.

    I have used several of their overhaul/rering kits to freshen up used Engines. Buick 350, 430, 455...olds 403, they are good kits.

    I say freshen the engine up, add a performance calibrated quadrajet, and work the timing for performance. Dual exhaust too if it's not already there.

    have fun!
  8. alec296

    alec296 i need another buick

    a 305 seems like a waste. might as well put in a 4.3 chevy v6
  9. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Not a regular POS flat tappet 305, a Vortec 305. That means factory roller cam engine that has 9.5:1 compression with heads that flow better than sbb 350 heads(unported vs. unported because the sbb 350 heads can be ported to outshine the Vortecs because porting a Vortec head doesn't really yield much extra flow) and if he got the combo right could have his car in the low 14s to high 13s in the QM with it. The one I put in my '64(I bought it setup with a sbc 283 in it with a powerglide that both needed to get the flock out!!) ran in the low 14s with the factory roller cam, RPM Air-Gap intake and a craptastic Edelbrock 600 cfm 1407 POS carb, with a better carb I think I could of made it into the mid to low 13s with it.

    Don't get me wrong, with a sbb 355 setup correctly will be a better runner than a V-305 with the extra 50 or more cubes if he decides on a stroker build, much more potential than the 305. Just saying that the V-305 is on a higher level than the 4.3 v6 even the Vortec 4.3L v6. The Vortec 305 heads make a non-Vortec smog 350 run great raising compression from 8:1 possibly lower up to around 9.5:1 waking it right up with more squeeze and better flow. Those V-305 heads are a great swap for the under 350 cid sbc engines as well because of its smaller chambers and superior flow compared to the heads they used for the older smaller cubed and or smog engines back in the day, like the 265, 283, 305, 307 and 327 engines.

  10. alec296

    alec296 i need another buick

    or " typhoon/syclone"
  11. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    I saw them on ebay, looks like a good rebuild kit they sell.
  12. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    You know your engines, What I was building up that 305 would easily have a 9:1 if not 10:1. What honestly stopped my from putting it in was that book and getting a new transmission. Unfortunately I dropped $1,300 not including the engine.
    The Buick gods came down and told me to rebuild my 350. Actually I really want to keep a buick engine with a buick car.

    I may be dreaming trying to get my Buick 350 at a 10:1 CR but at this point I would just like to rebuild the engine with a slightly more performance than stock. I do have a rear end with 3.73 if my memory served me right.
    I am willing to put at least $1,200 into it. So what I am trying to find is the right parts for the best performance. :bglasses:
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    You aren't dreaming, getting 10:1 compression is just a matter of the right pistons and decking the block some. Actually 9.5:1 might be a better target as you will want to use a smaller cam. read up on Dynamic compression,

  14. alec296

    alec296 i need another buick

    larry is correct . 10 to one isn't hard to get. but 1200 budget may be expecting a lot. if you just do a freshen up (rings and bearing,measure clearances) you can focus on headwork which is where the hp is. the 340p (hi comp replacement) ,h522 hyperutectic and 1734 (3.0 v6 flattops) all can get you close for compression .with the 3.73 gears I think the 284-88 would be a decent choice with a 2500 convertor, or go 310 cam with a 3000 convertor. the crower level 4 even a good choice .scott brown custom would be good too.
  15. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    FYI, To those wondering what book.
    Has anyone read this or skimmed through this book? It says in here that a stock 1970 4BBL 350 had a 10.25:1 CR. Is that accurate?

  16. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    No, in 1970, there were 2 different 350-4bbl engines, one was 9:1 compression(SB), the other was 10.25:1 compression(SP). The higher compression engine was the GS350 engine, but I believe you could order it in a Skylark. You would need to check for the 2 letter code stamped into the driver's side block deck between spark plugs 1 and 3. If the engine has been rebuilt, the letters may no longer be visible if the deck was surfaced. Also, those compression ratios may not be accurate. If you take the engines apart and measure everything, they are often less. Here is a good close up picture of the stampings.


    As far as that book is concerned, there is more up to date information available right here on this site.
  17. 8ad-f85

    8ad-f85 Well-Known Member

    Ummm...270 CFM isn't unreasonable for a skilled head porter with a flow bench. More is possible.
    It's enough to get a slightly lighter car into the 10's with a 350, built wild enough.
    No, I'm not discerning casting #'s...or promoting chevy anything.
    That being said, I wouldn't suggest swapping a 305 in unless puttering to the store with a down on torque type of thing is what you want.
    It would take serious rpm and gears to have much fun.
    A 10:1 400 hp 305 is a 7000 rpm peaky, fussy engine needing a high stall to get a heavy, low geared car moving....blah. :)
    A mild Buick would be much stronger through it's entire powerband.
  18. GNandGS

    GNandGS Well-Known Member

    Rather than risk souring your new found love of Buick, I suggest using what you have and changing the bolt-ons if needed with pistons and cam being the most exotic changes. Without experience or a buddy locally to help you, if things go wrong* you may be quick to rethink the Chevy - even if its your fault.

    Low stockish RPM torque is fun on the street and doesn't get you in a lot of trouble or require as many supporting mods. Less risk of mismatched combo also.

    In other words, IMO, stay mild THIS round and skip fancy rods etc and fix what needs fixing. Enjoy it for a while and build something with more power later - if you like. The book will make more sense then and you will have new questions.

    * There are threads here where machine shops messed up or some other issue came up.
  19. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    Man. Deffently giving me something to think about. I was talking to my buddy who rebuilds engine, he would help me rebuild the Buick 350. He mentioned, just like some of you guys suggested, is why take the engine out? no problem with the engine at all. Just was more curious what the previous owner did to it and able to answer questions about the engine at car shows or someone just asking me. I know that I want to replace the cam and want to take a look at the Pistons. Maybe rebuild the heads. So I guess I'm at that dilemma of should I throw money on new parts, where it could be uncall for. as far as I know those cam bearings or something else are still in good shape.
  20. pmuller9

    pmuller9 Well-Known Member

    The compression ratio will be determined by the new cam specs
    The power potential is determined by the head. you may want to wait for the new TA aluminum heads.

    Meanwhile contact your buddy that rebuilds engines and do a cylinder leak down test to see what condition your engine is in
    and also do a compression test to give you some idea what the compression is with the present cam.

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