Want more hp out my 75 Buick Lesabre 350 or swap it out for more power

As the cruising season coming to the end here in Minnesota i have come to the reality that im not happy with the speed and power of my 75 Buick Lesabre Convertible especially if i been driving my 69 Pontiac Grand Prix. Now my Pontiac 400 is powerful and im satisfied with it.

Now when i brought my 75 Lesabre back to life i knew the current 350 wasnt going be fast or powerful but i thought i could live with it, guess not. It runs great no issues except just not as quick as i want and am used to. So over the winter i want to upgrade the engine.

My budget will be 6000 maybe slightly more.
I prefer to keep it a buick but will swap it out if it going cost me more then my budget. I want to be pushing at least 350hp for a daily driver on nice summer days.

I know this is a Buick site so some of you wont agree with my choices but i can either go with a

383 Stroker 400 HP 450lb-ft Fresh Rebuild and with a adapter that mates with my buick transmission bellhousing for 4800

Ls 5.3 engine. Here they go all day long for under $500 in our local junkyards. And will easily give me my 350hp that i want.

Or can my buick 350 be rebuilt to push out 350hp within my budget and if so who is a good engine builder around the twin cities area for buicks? I heard of wagmon engine rebuilders but have never been there so they are an option?

 

That seems like a generous budget to upgrade the existing Buick 350. You could put the TA performance Aluminum heads and intake on there with a good Carb? I can't speak to the local engine builders in your area...

http://www.taperformance.com

 

easiest and cheapest way:

buy a 455, sell the 350
spend some money on 'go faster goodies' and drop that engine in your b-body!

 

I had a 75 LeSabre convertible w/350 as my first car.
It wasnt fast, but neither was the 455 of the same year.
The 350 was 165 hp and 265 torque.
It was a measly 8 to 1 comp ratio and wimpy cam.
It did have an "ok" rear gear... 3.08
This is what Id do,
Up the compression to 10 to 1
A mild TA cam, if you can go roller cam, do it.
TA's aluminum heads if its in the budget, but Im sure the iron heads would work just as well for the purpose of the car, a cruiser with some power.
If you do go 455, you'll basically be starting from scratch unless you've actually driven the car the 455 was in to verify if its healthy.
The biggest gain going 455 your going to "feel" is low end torque.
Im a "work with what yah got" kinda guy

 

Everyone who says go 455 is right. Going with a 350 is not bad either. Your model year is the biggest disappointment in the fun category. No compression and smogged to death till they can nearly not breath at all. But, some new pistons and machine work make that motor a whole different animal. Not to mention you can make it “look” the way it was made if you care about that. Either way, peruse the TA catalogue and enjoy your decision. With that budget you could build a healthy mill with either choice.
And cool car too!

 

All decent options. But I would look at rear gears and trans upgrades also. Alittle more convertor and a 2.75 first gear set in the 350 or 400 trans you have will increase the off the line go factor. I would go 350 . Plenty can be done. 350 hp isn’t a hard goal either. Big valve ported heads, forged pistons around 10 to 1 , zero deck, a decent cam that’s proven in that power range. But I would go with something that makes high lower torque also since it’s a big heavy car.
have you looked at trishield performance? Contact Jim . He runs this board.

 

Several thoughts to add: How tall and heavy are your rims? If they’re taller overall than the factory combo, you’re effectively decreasing the rear gear. If they’re heavy, you’re adding unsprung weight which really hurts coming off the line. If either or both of these are true (and you want to keep the rims) a rear gear swap would help a lot. A stronger Buick 350 built to make torque also will help, and a Buick 455 built fr low end torque will help more. One weak link of the ls engine, especially the 4.8 and 5.3, is lack of torque at low rpm. 383s aren’t really torquers, either. Keeping a Buick 350 would need no fabrication, and a 455 would require a little. The chevy swaps may end up nickel and diming you to death will little stuff. Not to mention they’re just wrong.
Patrick

 

I’ll admit I’m a bit of a Buick purist. With 350 HP as your goal it can be easily achieved. The aluminum heads from TA would be a good choice. Not just for better flow but they will allow higher compression due to better heat dissipation. Going with a roller cam will be costly and will most likely break your budget. Ask me how I know LOL. I always allow for cost overruns no matter what the project, car related or not. Good luck, build the 350 is my opinion. Going with an LS motor adds the cost of an EFI supportive fuel system.

 

Start with the following modifications:

-Everyday performance rebuilt Q jet
-re curved HEI distributor to give 14 degrees initial timing, 32 total, plus 10 degrees vacuum advance.
- headers and dual 2.5” exhaust

these mods will wake it right up, and if that isn’t enough then find a set of 68-70 heads, mill them 60 thou, shorter pushrods, and a TA 212 cam. That’s all you need for a strong street car.

or save up a bit more and do forged pistons and the TA heads, with a mild rebuild.

 

my 72 with a 350 run pretty well to be a stock car minus the 4 bb swap and its using an adapter plate currently. i would like to see it make 300 hp by the time im done with it though.

 

Do what Sean says, used possible ported, heads from 68-70 isn't that expensive, and combined with the other things, I think you'll be happy.. It's also the way with the least amount of work..

 

The last statement Sean made is what I’d go with. At least build a solid bottom end as a foundation. This way it will handle whatever you throw at it in the future. You may even find a set of iron heads ported for sale from someone that went aluminum. Just my .02

 

Well you could off set grind the Crank some to gain more cid / stroke and to get things back as needed And maybe save on custom Pistons since there deck can likely be cut down atleast.030" maybe more!

 

Offset grinding the crank won’t yield much better to overbore the cylinder. Sixty over gives you 360.43 cubes. Add .010 to the stroke gives you 361.46 at 60 over. Not much to gain there.

 

I'd do new forged pistons with adjusted comp height to give you 10.5 comp. Cam, big 4bbl carb, headers and gear. You'll be smoking the tires up, having fun....

 

It's a big car, you need a big motor. Find a 70-72 455 and do a thorough but basic rebuild. You'll net about 400 hp and a boatload of torque. You won't be disappointed.

 

Ok update..I ended up getting lucky and stumbled onto a 73 buick 455 from a 73 lesabre with only 62,000 miles on it..Since im going have it on a engine stand in my garage it going be easy for me to upgrade it with a few things..

It started up with no smoke or noise..has slight oil leak from either pan or rear main..both will be easy to fix since it on a stand.. im shooting for 350-400 hp still..

I was thinking of going with the TA-212 cam kit and the Performer or B4B intake. And a set of TA 1-7/8 headers with a hei distributer and maybe a holley 750 carb..Will this make my 350 to 400 hp?

My gears are 3.08. Will i need change my stall to get the most out of my engine? The tranny is a 350.

Also if i kept all the above and went and had the long block rebuilt with 9.5-10:1 pistons will what would my hp be or keep the pistons stocks will i see a difference? I was told are stock intakes are good enough wont notice any gains from the eldebrock intakes?

 

With your budget of over $6000: first try to find a rebuilt TH400 + drive shaft.

 

I second the idea of more gear in trans to go along with your new power plant.......sometimed effective using the power you have is better than making more.

The 73 motor probably made close to 300ish hp at the crank and i would guess torque to be just under 400........seeing this isnt a vehicle going to be run full out all the time i would think the th350 should live behind the motor..........but there might be a few updates it wants done......the th400 would live better but does eat up more power to get through the trans due to the internal weight of the drums and stuff inside........a 2.75 gear set is about 500 new and if having the trans gone through really should add anything to the bill in the labor area.

I would guess the average cost to bottom end buick rebuild is about 3000ish with proper block work but not going racecar crazy

When it comes to getting a big heavy weight moving torque is needed.......and low rpm torque requires cubic inches.......it become pretty standard and easy to build a 482 buick motor.......the next best thing is prooer working torque conveter and gear ratio......upping the low gear won't change the final driving rpm,

As mentioned there is a great buick guy and he does trans and converter too in your area that many ppl are very happy with. Give Jim a call and talk to him b4 you spend any more money

But your numbers and budget seems reasonably obtainable