I recently bought what was said to be a 383 stroker LT1 1994 Corvette coupe. This Vette has a lot of reciepts with most of the work and things included in it. I am a mechanic by trade, but have not gone so far as to educate myself on building stroker engines, basically worked many stock engines and other mechanically stock issues. So I won't say that I am real smart about stokers in general, or at all actually, I have been reading lately about 396 LT1's and wonder if that is really what I have or the 383 as stated when previous owner was selling it. I think the guy before the previous owner was the actual person who did had the stroker built. I have added some of the things on the custom page that I made for this Corvette on a page on my website here: http://www.fastcoolcars.com/1994-corvette-6spd.htm Most of the stats on the build are about 3/4 the ways down that page. I'm just curious, and I have not gotten it dyno'ed and the previous owner did not have any information on that either, he actually told me that the car was still running on the stock tune after the stroker build? It seems to run fine to me, although he says a lot more power should be had from a retune, any idea what kind of HP I should expect, and torque? Thanks in advance.

 

Typically you take a 350 block, which is a 4" bore, bore it .030" over to 4.030" and then replace the the 350 crank (3.48" stroke) with a crank from a small block 400 (3.750" stroke), with mains ground down to the 350 main size, and you get 383 cubic inches. The pistons have to have the correct pin height to compensate for the longer stroke.

Nowadays there are ready made aftermarket cranks and pistons just for this, including those for 1-piece rear main seals.

The 396" motor is a 4.030" bore and 3.875" stroke crank (3 7/8"). Same as a 383 but with a 1/8" longer stroke, and different rods and/or pistons to accommodate. These parts are less common than for the 383 builds and sometime require more work for block and camshaft clearance.

Dan

 

This is what I got off the hand written reciepts from 2 or three different speed shops and parts places, so some of the names or descriptions may be a little off, shouldn't be much though, will that information help in figuring which stoker I have, and maybe a good estimate on the power I should expect to see from a build like this? Thanks for your explanation on the differences between the 383 and 396 stokers. Here is what I know of form the slips that came with the Corvette:

383 Stroker Build (2500 miles ago)
Complete Head Job
Heads Milled
Bore V-8 Block
Balance Assembly
New Delco Water-pump assembly w/ thermostat
New GM radiator cap
New GM Belt Tensioner
New GM Idler Pulley
New GM Radiator Hose
22 New Hose Clamps
Power Steering Fluid Change
Anti-Freeze Change
Custom New High Pressure P/S Hose
New Fuel Pump
New Fuel Filter
Cloyes Performance Timing Chain kit
High Volume Oil Pump
New Pick-up for Oil Pump
New set of Forged Pistons
New set of Rings
New Rod Bearings (Race)
New Main Bearings (Race)
Pro Series Rod Bolts
Fel-Pro (Conp.)
Fel-Pro Head Set
Steel Crank (1 Piece)
Fervea S.S. Valves
Valve Locks
Retainers
Isky Springs
Isky Roller Lifters
Isky Roller Cam
New Cam Bearings
Recondition V8 Rods
Heavy Duty High Performance Clutch Assembly ($975 kit alone)

The guy I bought it from said it had a new cam, not radical, but not stock either, that's all I know about that.

Ron

 

So why are you thinking it's a 396?

 

I'm not thinking it is a 396, and I see that by what was said above the differneces are in the 3.875" stroke rather then the 3.750" I do not have enough information I see to be able to make the conclusion one way or the other, so I will go with what the previous owner told me...383 Stroker LT1. Do both 383 and 396 strokers produce about the same extra amount horsepower? Or are the variables in other parts used a factor probably in the finial answer? I guess I need to get it to the dyno and have a re-tune done at the same time. I'm just a little curious to know how much more HP does one get usually considering the starting stock 94 LT1 is 300 Crank HP right?

 

Let's say a given engine makes 1 horsepower per cubic inch. Then, all else being equal, a 396 will make roughly 13 more hp than a 383.

 

That sounds like a good explanation of it, and easily understandable too. I appreciate it