L-81 to 383 stroker

[gedmeyer]

Is there anyone who upgraded their L-81 engine to a 383 stroker? If so, what did you do? I'm on a budget and I'm thinking a 383 is the "cool" way to go.

I was just curious if anyone was able to use their L-81 block and heads.


p.s. i took the intake off today to get it cleaned up and looking at that pathetic L-81 makes me want to give her more power and look pretty

 

[DDLS3]

I haven't seen scott81 around for awhile, you might send him an email. He changed engines in his 81 to a 383 stroker last year. I think the sharktank website is back up, scott has a lot of info and pictures posted there.

 

[gedmeyer]

yeah, i've been to his site numerous times. I think he did a very nice job on his car. The only thing is that he did a complete engine swap (i thought anyways.) I'm looking into rebuilding my L-81 to the stroker. thanks

 

[MoeJr]

I would just rebuild the stock L81 and warm it up a bit. A good intake,cam and head work will wake that car right up. ALso a good true dual exhaust will help too. Also u can swap out the rear gears for a set of 3.55's. I think 81's came with 2.87's. Just my .02

 

[gedmeyer]

my thinking is that, if i'm gonna spend the time and effort rebuilding, I might as well go for something that is gonna have some "bang" that I won't get tired of. Realistically, what kind of bang can I get from doing that kind of work? As I see it, changing the internals is the only difference for a 383 (minus the boring).

 

[MoeJr]

How much bang you want? I mean a streetable 350 can make 350-400 hp. Depending on your budget sometimes a crate motor makes more sense than rebuilding your original engine. Also remember that you can build a 383 but it still will be sluggish with those hi way gears and stock torque converter. Whenever I have wanted to upgrade any of my "toys" performance I have always started with the rear end,trans and exhaust. Makes no sense to put all the money in the engine and not have everything else ready to compliment it. Being in the suto repair field I have had lots of cars come in with "built" motors only to run like a yugo on 3 cylinders cause everything else was mismatched.

 

[GerryLP]

One other option for you to consider is to get a solid 350 block, and get machined (if required) to accept the 400 CID crankshaft.

I like the feeling when I decide to "abuse" my replacement engine and not risk damaging the L81 engine. That engine is safe and sound in my garage in case I decide to restore to specs.

 

[gedmeyer]

Well fellas, I decided to rebiuld. My father is friends with someone who owns a machine shop and is going to do everything, i just have to pull the engine and dissassemble it.

What is this "everything" I speak of, well, stroke it!!! I'm psyched. Gonna be a hell of a ride by next spring. Anyway, I should have the block out this weekend!

 

[gedmeyer]

Oh, I am using the L-81 block. I decided that, unless an epidemic takes out every other corvette on teh planet, mine will never be a collectors item. So, I'm gonna "personalize" it and make it real desirable. It's gonna look mostly stock, but she'll be packing some heat with a few little aesthetic refinements.

 

[Dave L.]

Thats what I like...A man with a plan.
Have fun Tim!!! keep us updated as you go along.

Dave

 

[gedmeyer]

I'd be willing to bet that a good portion of my "updates" will come in forms of questions on something comes apart/goes back together! haha. I'm really excited about the whole project. It's almost too distracting from my college work. oh well, the sacrifices we must make

 

[AUSSIEVETTEMAN]

Gedmeyer

I put an Edelbrock Performer manifold and Edelbrock QJet carb on and had the catalytic converter cut out of the exhaust. The exhaust system is a true twin system, running two pipes to the rear mufflers, with no equaliser pipe.

All the work was done in stages.

First the exhaust, this mad a difference, I reckon around 5 to 10 neddies extra and the sound was deeper, but not too barkier, if you know what I mean.

Second was the carb and inlet manifold. This made the most amount of difference. The engine just came alive!

I am enclined to agree with Moe Jr about the changes he has made. I haven't changed the gears in the diff though, they are still 2.87's. She won't break traction off the mark, just grips in with those new Falken Tyres and put's you back in your seat.
That's the way the boys at GM designed it anyway. I was watching a video on the 81 the other day and they mentioned it on there. I would like to change the gears to fry a little rubber now and then, it would be good to see those Falkens burn white smoke, but think that my freeway driving might be affected. We have a 110 KM/H speed limit on our freeway here in some parts (that's around 68 MPH) and she sits on around 2500 rpm now.

Good luck with your rebuild.

Cheers

Tony

 

[bossvette]

the "383" is a 350 block bored .030 over (pretty much the standard bore job) with a ground down 400 crank in it. In the early days it meant using 350 pistons and 400 (5.65)rods or more expensive special pin location pistons with 350 (5.7)rods.
due to the popularity of this "Hot Rodders" engine combinatin "383" cranks are widely available from many sources and even GM is building "Crate" engines at this size.
I don't want to start any debates, but my opinion is the 383 is a much better combination for a street driven Vette. Built with a leaning twords torque you will have a much more docile monster.
I have a 383 in my 76 and it is much more easy to drive then the origional l-48 (or whatever it was at 350) even though spec wise (cam, heads, ignition, induction,etc) it is "wilder" you would not 33 inches would make that much difference.
Craig sr.

 

[gedmeyer]

Hey all. I just pulled the block (heads were already off) this afternoon! Didn't go too bad except for 2 bell housing bolts that gave me a little attitude. But she's safe and sound now! I took a bunch of pictures, so hopefully I can get one or two up to show you!

p.s. this is my first engine pull!

 

[texancanuc]

383 or crate

i just had a new(seasoned) engine installed it is bored .30 over moderate cam, good heads edelbrock performer intake, 600cfm square bore and i have headers with open( monza tips only) exhaust
excellent so far but i havent been over 3grand on the tach yet, still breaking her in
has anyone else done a swap like this and wound up with a boggy brake pedal is it the vaccuum thats the cause or am i leaking air into the brake system AGAIN
P.S as soon as ive got this baby ready and broke in im goin PONY hunting:crazy