I know I saw this here before but I just can't seem to find it. What is needed to go from a 350 to a 383?

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"Though I cruise through the valley of Rice I shall fear no turbo, for torque art with me."
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1985 IROC-Z w/T-tops, 305 out and 350 L98 TPI engine in, Hooker Super Comp Headers, 3" Hooker Super Comp Cat-Back, 3" CatCo Cat, Rebuilt TH700R4 with Shift kit, 3.73 Richmond gears, Auburn differential, Accell SuperCoil, Accell 8.8 racing wires, BBK AFPR, Homemade Ram-Air (thanks to Andris Skulte), MAF screens removed, Dropped A/C, TB coolant bypass, Hurst Dual-Gate Shifter, Air Foil, K&N filters, Holley performance fuel pump, Spohn Subframe Connectors, Re-located Spohn Lower Control arms, and more to come.

 

First of all, you need a bigger crankshaft. The stock 350 crank has a 3.48" Stroke, a 383 has a 3.75" stroke. You need new pistons to accomodate the larger bore, a 383 has .03" larger bore than a 350, and new rings to match. You may also need new connecting rods, main and rod bearings, etc. Think of it as an expensive rebuild.

Pretty easy to find the parts, kits are for sale on ebay all the time as well.

 

You may also need to clearance part of the block to clear the connecting rod bolts. It's a pretty minor modification but you do need to be aware of it.

BTW, I have an externally balanced 383 recip assy. here that I'm going to sell. It has newly redone forged pistons with CBC2 thermal barrier coating on them, and the crank is newly reconditioned and is for a 2-piece rear main seal design block.

 

Just completed my 383 project in my 86 vette...didn't use a L98 block because it wasn't a 4 bolt main. Upgraded my fuel systems and massaged the L98 alum heads...hardest part of the project was programming a solid EEPROM Chip to make my ECM powerful enough to handle the job...

Lessons learned...program your own chip

 

Thanks for the info guys. One more quick question. What would be a better mod to do first. Bore and stroke to 383, or pick a good heads and cam combo? Everything else I've done is in my sig. Thanks again for the help.

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"Though I cruise through the valley of Rice I shall fear no turbo, for torque art with me."
-----
1985 IROC-Z w/T-tops, 305 out and 350 L98 TPI engine in, Hooker Super Comp Headers, 3" Hooker Super Comp Cat-Back, 3" CatCo Cat, Rebuilt TH700R4 with Shift kit, 3.73 Richmond gears, Auburn differential, Accell SuperCoil, Accell 8.8 racing wires, BBK AFPR, Homemade Ram-Air (thanks to Andris Skulte), MAF screens removed, Dropped A/C, TB coolant bypass, Hurst Dual-Gate Shifter, Air Foil, K&N filters, Holley performance fuel pump, Spohn Subframe Connectors, Re-located Spohn Lower Control arms, and more to come.

 

I built one a few years back. You WILL need to clearance the block for each cylinder, just below the pan rails when viewed from the pan side, to clear the rod bolts when they come around. I also had to notch one piston skirt a tiny bit to clear a crank throw (I used a stock 400 crank with mains turned down). You will also need to grind a tiny bit off the head of one of the rod bolts to clear the cam as it comes around the top side. I'm not sure which rod bolt needs to be clearanced - it's documented in a book that I have. I think the book is "how to hot rod small block chevy's" but I'm not sure. I have several of these books however one of them tells you all you need to do to build a 383. If you want to know what book it is, email me and I will look through them and find out which one it is.

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'82 TA "FRANKENBIRD" - built with various F-Body parts from '82 to '96.
CURRENT: '91 305, '96 T-56 6 speed, 3.42 POSI, '89 WS6, '86 TPI, SLP 1 3/4" headers
SOON: 350, Trick Flow TW heads, GM-HOT cam kit, PBR disc