Item Posts    Sort Order

Building a 383 stroker for 89 TBI Truck. Questions! Need help!

I love my Chevy Chevette!
Posts: 1
Joined: 03/09
Posted: 03/19/09 06:38 PM

Okay. I have been doing a frame-up restoration on my chevy pickup. It is a 1989 4x4 V3500 pickup (Old body style). The paint and body work, plus the new interior and wiring cost more than I expected and kept my pockets empty for awhile. Anyway, I am going to build a 383 stroker. I want to keep the factory TBI fuel injection, although I may convert to TPI later. Anyway, I decided to use an aftermarket block. I realized that there was no aftermarket replacement for an 87-95 1-piece rear main block, so I am now trying to decide how to configure an older style block to use a hydraulic roller cam (obviously I can't use the OE style cam) and also, what dimensions the block and rotating assembly need to be. I figured I would just have a custom cam made by Comp Cams to fit the block but be compatible with the TBI computer. As far as the bore and main sizes, I have yet to figure out. So here is where I need help:

I have found several different configurations for a 383. I found that most used 400 mains but some used 350 mains. Also, I found that some used 5.700" connecting rods while others used up to 6.000" rods. Even the bore varied on some. I really don't know which direction I should go or what the differences are between the bore, stroke, and rod length, and which one I should use.

Should I order a block with 400 mains or 350 mains?

Should I use the 5.700" rods or longer?

What bore diameter should I order the block with?

Keep in mind that I do want to keep the engine streetable and would like to use the best and most reasonable setup to obtain 383ci. I assume the shorter rods would be desired but I really don't know. Any help would be awesome!

Also, if you do know of a good aftermarket replacement block for the 87-95 1-piece blocks, please direct me to it, because I would rather use that. I know GMPP has one but I want and need the extra strength and versatility of the performance blocks. I planned on using a World Motown block, with World S/R Torquer Heads, and a SCAT forged rotating assembly with H-beam connecting rods.  

Post Reply
I mow my lawn and find Chevys
Posts: 1985
Joined: 10/03
Posted: 03/20/09 03:40 PM

Since you want to use an aftermarket block and crank it won't be an issue to use 350-size mains. The aftermarket is well aware of this switch as MANY people have been making 383 "stroker" engines 20+ years. I'm sure structurally the 400 mains make for a slightly stronger crankshaft but this just really isn't an issue. There will be other weaker links in the chain, so to speak, around terribly high horspower ratings anyway that would make this switch almost completely unnecessary.

I would use a 6" rod while you're using all of these fancy aftermarket parts. It leaves ample room for a ring pack (not a lot, but a satisfactory amount), results in a lighter piston, and creates a more "satisfactory" rod to stroke ratio.

I would probably order a block with a 4.0" or 4.03" bore. I would also check on having the block manufacturer do the honing, or have your machine shop of choice do it (better be a darn good machinist with darn good equipment to put a $2000 block in their hands though!). Any of the aftermarket blocks you will be dealing with should be thick enough to have at least a few rebuilds in them at a 4.03" bore. The 4.03" bore makes for approximately 383 cubic inches.

You should definitely be looking at a better cylinder head if you're going to be using all of these expensive components underneath them. Since I see you like World Components, I would look at their aluminum Motown heads with a 215cc runner. No reason to skimp and buy iron heads.  

Post Reply