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

Thats awesome!
Are you buying the whole car or just the engine?
Get the whole car if you can, as there are alot of parts that will make the swap easier such as:
Double hump crossmember for dual exhaust ( '75 is single only)
Motor mounts
fan shroud
400 trans
I'd snag the rear axle too just because
Only bummer is the rear gear for the 455 big car was probably 2.56 verses your current 3.08, They MIGHT be the same ring gear size, Im not sure, but the current axle in your car will hold up fine, its a beefy guy.

 

Unless their gonna mill the heads or change pistons, go for the Torque. Get a 2000 torque converter and a 2.75 gear set. With the 3.08 that should be in the car ,it should move well from a start. Small diameter tires will help this also. Are you gonna make 350-400 with the 212 cam , intake and headers? I doubt it unless you go into engine and start with pistons and head work. And then I would get a 284-88 cam set advanced with a 2600 convertor. Tuned well with 9.5 compression, it should make 425 or better with 500 plus torque.

 

I have a th400 in my garage that came out of my 68 rivi..Been sitting in there for 6 years..i been meaning to get it rebuilt because it only goes in reverse..

 

Im getting so many different answers lol..I rather stick to the 3.08 gears and my car wont and is not a daily. Only weekends and nice weather. I want it to be streetable..Not building a race car but want to be able to smoke the tires at the stop light just like i can in my 69 pontiac grand prix. And also be a nice cruiser. Hope that helps

 

Im going email Jim tonight and see what he says.

 

You won't go wrong talking to Jim.

Also, if you are hoping to save a few bucks, the Turbo 350 with a few inexpensive mods will hold up to a mild non-race 455 for quite a while. The Turbo 350 has a slightly lower first gear than a turbo 400 and it is lighter/lower HP to spin. It is already setup in the car and there's nothing to change.

 

The 350 trans can hold up to a lot of hp I ran nitrous on my 350 to a high 11's and it was just fine.

There was a guy here that ran a 350 trans behind a 455 and he said it held up just fine. He races all the time.

your 308 gear is just fine keep it and use cam and such to match that, if you get the comp up to 9-9.5 you can probably run the 212 cam but no bigger. Heck I ran the 268 Comp Cam shaft with a totally stock 71 8.5 engine with headers. It ran fine but it was a little slow out of the hole but at 3 grand look out.

Get you comp up to at least 9.0
So use about a 2200 stall and your 308 gear with about a 212 cam or smaller the 112 cam would be better and you will be good.

Nothing will work better than getting the heads ported some do what money allows. Doesn't have to be a lot.

 

Get a pair of these, bump your compression up.....
https://www.ebay.com/itm/233511371928

 

Those are for a 350, the thread starter is swapping the 350 for a 455:

 

Your 455 heads stock flow about 215 cfm@28" @ .500" lift on the intake side and that full 215 cfm could make you 55 hp per cylinder.

To attain that 55 hp per cylinder you will need to run .550" lift to average enough flow to do that 55 hp per cylinder, to make 400 hp you want to run a Cam of .480" to .500" lift.

 

I See...
He's still in the mouse motor section. Threw me off....

 

Ok what cam would you run with it? With just a cam and headers? And keep the stock rockers Im keeping the qjet that it came with and having it rebuilt

Also why would you run the stock cam? I been reading all i can about cams and it seems to b so many choices.

Im starting to worry after seeeing some people have issues with swapping in new cams and not enjoying the way it drives any more..

The 350 i got in there now is dependable and no issues after i changed the radiator so i want this 455 to b exactly same way. Jump in turn key and drive with occasional burn outs.

 

Did this new board member from California contact you about the 350?

Link to the thread

 

Since the car runs and drives I would leave it together while you sort out the 455 and then swap it in. I wouldn't touch the Th-350, if it works fine leave it alone. At very least mill the heads 60 thou to get the compression up, shorter pushrods to match. A TA 212 cam, and a new timing set would be good. stock intake and a fresh Q jet (https://quadrajetpower.com/) is my vote.

 

Easy answer if you're open to accepting the advantages of retaining the Buick 350:

http://v8buick.com/index.php?threads/tsp-level-1-350-buildup-info-and-dyno-results.153248/

Advantages include retaining the stock (or slightly modified) wire harness, fuel system, cooling system, engine mounts, etc. You can even get away with stock (or lightly ported) exhaust manifolds if you get tired of the hassles related to full-length headers... if you're willing to accept the power loss compared to headers.

Send or transport your 350 to Jim Weise at Tri-Shield Performance (referenced elsewhere in this thread) and let him do his magic. You'll thank yourself many times over for going this route.

 

My thoughts exactly.

Why not send the 455, that he already has, out to someone to have it build?

 

If it hasn't been run for awhile those main seal leaks may just go away as the rope seals absorb oil.

Jim