383 question

[98k2500]

I know not the best approach but I'm really curious if any one has ever used an aftermarket 383 crank and reused all of their parts from a 350? Since technically you don't have to bore the cylinders .30 over could this be done to build a low budget 383? Purchase the crank, hone the bores,new rings and do any clearance work for bolt heads on the block if needed?

 

[RichLo]

You may be able to re use the rods but I'm pretty sure you'll need new pistons otherwise you'll be slapping the head

 

[Erik the Awful]

New pistons are a must, for the reason cited above. Boring is not a necessity, but you'll want to measure the pistons and the bores - my .030" over Sealed Power pistons I put in my TBI rebuild measured 4.030" instead of 4.028", and my machinist had to bore to 4.032". You might end up working that hone for a while.

https://www.summitracing.com/search...-block-gen-i/bore-in/4-000-in/******/3-750-in

 

[TechNova]

you won't have a 383, it will be a 377.

 

[Manimal]

make sure the crank matches the block...1pc seal or 2 pc seal. You can reuse your stock 350 rods, but honestly by the time you rebuild them with quality ARP bolts, you're only a few dollars away from a NEW set of SCAT/EAGLE rods. Clearance the bottom of the cylinder bores. Check rod to cam lobe clearance and assemble just like any other small block chevy.

 

[Erik the Awful]

Replacing rods and pistons adds about $325 to your build. Cheap enough that I did it on my 'budget build', but if I didn't need an overbore I'd probably have stuck with stockers. If you're going 383, at least pistons are necessary, and the $225 you save by reusing the rods are eaten up by the $90 for rod bolts and $70 for having the machinist install your pistons. At that point you're only $60 from new floating-pin rods.

Pressed pin rods = paying your machinist to install the pistons - the stock rods are pressed-pin.
Floating pin rods = easy DIY, but pay attention to whether they take spiralocs or wire locks - they SHOULD come with the correct locks.

 

[Old Gasser]

I built a 383 (actually mine was 385) in the early 80's, before any of the kits were available for this. My machinist had the internals from a 400sbc that was in a boat, that had frozen and broken the block. We used the stock 400 5.57' rods, the 400 crank, .040 over cast replacement "rebuilder" 350 pistons, and the #441 casting heads that were stock on the 350 in my 1970 pickup. It all worked well. I drove it for @ 70K HARD miles(it was too fun to drive!) and it performed flawlessly. And very well.

Hope that helps.

 

[98k2500]

Replacing rods and pistons adds about $325 to your build. Cheap enough that I did it on my 'budget build', but if I didn't need an overbore I'd probably have stuck with stockers. If you're going 383, at least pistons are necessary, and the $225 you save by reusing the rods are eaten up by the $90 for rod bolts and $70 for having the machinist install your pistons. At that point you're only $60 from new floating-pin rods.

Pressed pin rods = paying your machinist to install the pistons - the stock rods are pressed-pin.
Floating pin rods = easy DIY, but pay attention to whether they take spiralocs or wire locks - they SHOULD come with the correct locks.

What about balancing? Say I go with new crank rods and pistons, then I'd have to pay machinist to balance everything or is balancing really not required?

 

[Manimal]

I have balanced EVERY engine I have built. Stock to performance. I also use a torque plate for honing for every engine I build.

 

[Manimal]

Also, if you buy a new crank, get a Scat. Every Eagle crank I have had needed work, I just send them to get .010/.010 turn right out of the box, so I quit buying them. Scat have been great right out of box.