Cam choice- LT1 or summit 8800?

[L31MaxExpress]

I have run nearly 9:1 dynamic with iron heads and pump gas without issues with good quench. You will never do it with GMs crappy dished piston design though. GM engineers shot their foot off using them rather than a D-shaped dish that matched the chamber. They have learned though. Modern stuff has some crazy piston designs.

 

[L31MaxExpress]

The cam currently in my 383 was custom spec'd and ground by Comp cams for a 9.6:1 350. It is horrible in an 11:1 383 in terms of idle quality and off-idle torque, I can only imagine how horrible it would have been in a 9.6:1 350. The LSA is too tight on a 108* and the 10* exhaust split is terrible for low-speed power. I have a single pattern, 112 LSA replacement for it when I find time to swap it in. Engine analyzer show the engine will be up nearly 40 ft/lbs at 1,500 rpm with the new cam and it will gain 3 in/hg idle vacuum.

 

[Scooterwrench]

I have run nearly 9:1 dynamic with iron heads and pump gas without issues with good quench. You will never do it with GMs crappy dished piston design though. GM engineers shot their foot off using them rather than a D-shaped dish that matched the chamber. They have learned though. Modern stuff has some crazy piston designs.

How are you measuring dynamic compression?

 

[L31MaxExpress]

How are you measuring dynamic compression?

Pat Kelley DCR calculator

 

[Scooterwrench]

Pat Kelley DCR calculator

So theoretical.

 

[L31MaxExpress]

So theoretical.

Compression tester backs it up. The iron head 350 in the 87 is 195 PSI. The 383 in the 97 is 230 psi.

 

[Hipster]

Back in the old days those are what GM used on all their small blocks. Never had problems with them unless you tried to melt the engine. If you install them dry you are setting yourself up for problems. Smear a thin coat of non-detergent 30w on the heads and block surfaces,torque them down right and they'll last forever.

Probabably talking before my time, Never disassembled and oem one that had straight up shim gaskets unless they had been into and found something like a Fel-Pro, found many similar to some Victor HG's, embossed steel but laminated coatings. Multiple factors involved in HG durability, heat cycles, getting toasty sitting in traffic, hammering on your stuff while it's ice cold, deck and head surface condition, etc,

Oil them, coat them, spray them with aluma paint etc, the box of band aids gets big. If the GM ones were that great no one would have deviated including the bean counters at GM.

 

[L31MaxExpress]

Probabably talking before my time, Never disassembled and oem one that had straight up shim gaskets unless they had been into and found something like a Fel-Pro, found many similar to some Victor HG's, embossed steel but laminated coatings. Multiple factors involved in HG durability, heat cycles, getting toasty sitting in traffic, hammering on your stuff while it's ice cold, deck and head surface condition, etc,

Oil them, coat them, spray them with aluma paint etc, the box of band aids gets big. If the GM ones were that great no one would have deviated including the bean counters at GM.

I had several 70s and 80s engines that I pulled apart that had thin waffer steel gaskets. All the 305s had them.

 

[tayto]

gm used shim type gaskets right up until the TBI era. Last small block i took apart was an 87 TBI block and had .016" head gaskets. like l31max says, with the D-dish quench isnt really important anymore...

 

[Connorpod]

I Installed a Sum8800 in my 95 Chevy k2500. It took a bit of chip tuning to get the back fires out the intake sorted out. However it has plenty of low and top end torque. Love the idle sound. Would recommend for the price.