Hey all - I'm dropping my new 383 in my '88 SC...

It used to have a 305 TBI, but I'm going to 383 carbureted.

I had a local shop put together the bottom end+cam as part of a $1500 package (including all machine work from rusty 'ol 350 block):

SCAT 383 crank
Probe Aluminum Forged Pistons
Comp Cams Extreme Energy 268H

Before I got back the finished bottom end, I bought these

GM Performance Parts Vortec Heads ($500/set assembled)

All is good, right?

Well, I was looking a a Jeg's catalog today, and the last line of the product description for these heads says ".475 Max Lift".

I have some concern, as the Comp Cams page says:
Lift: .477''/.480''

Woah, Nellie! Hold on! WTF? Am I in trouble?

It seems weird that if these two didn't work together, world-famous Salee Chevrolet wouldn't put them together in this 350 Super Deluxe crate engine, right?

Can someone shed some light on this? I'm getting worried!

 

.475-.480" is the typical max recommended lift on stock Vortec heads with good valve springs and retainers, and verified retainer-to-guide/seal clearance. They used upgraded springs for the .480" lift cam.

It would still be a good idea to have the guides cut and good springs installed to take the lift of that cam. Pretty standard operation with Vortec heads. Playing with fire if you don't do anything. Springs/retainers are a must.

Wouldn't be a bad idea to pin the rocker studs, or have the heads machined for screw-ins while you're at it.

 

five7kid - thanks for the info...

I've now heard that I should rethink using these heads, unless I want to replace the retainers and springs, not to mention having the press-in studs replaced with screw-ins by a machine shop.

Curses! Any other thoughts?

 

i think you should just take the heads to a decent machine shop, and have the machine work done..

its REALLY EASY for them to do.. its cheap... and you can then use them without worry.

dont be intimidated by it, just do it

 

I assume you purchased the cylinder heads from Salee Chevrolet (I've purchased a few engines there too). My suggestion is that you give them a call and ask your question. They'll give you the straight scoop and let you know your options. They might even take your heads back on trade if you want to get another set machined for different valve springs.

Good luck with your project. Sounds pretty neat!

 

Cool - thanks for the confidence-nudge. You are right - I needn't be too worried. :-)

 

Actually, no. I bought the heads from Summit Racing. I think I'll keep them, I'll just get the machine work done to make it work...

Thanks,
J