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Heads

Jonathanlackey said:
my dad has a set of 062 vortec heads that I can use but we were warned about gen 2 vorted heads and intake making to much compression on a gen 1 block
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Huh? I've never heard that. Sure the 70s had compression ratios in the low 8's or worse, but remember earlier small blocks came with 10-11:1 compression from the factory. There's no reason a gen1 block can't take some compression.

The issue with compression is going too high and getting stuck running higher octane fuel to ward off detonation. Vortec's have small chambers so if you may have to use a thicker head gasket to negate some of the chamber size and decrease compression.

I'd suggest to figure out what you have and play with the compression calculator on Summit just to get a feel where you are at.
 
Jonathanlackey said:
my dad has a set of 062 vortec heads that I can use but we were warned about gen 2 vorted heads and intake making to much compression on a gen 1 block
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Your present compression ratio on a factory stock 73-80 350 truck engine should be 8.2-8.5 w 76cc heads.
the vortec heads will increase your cr about 1 full point. I ran my 79 truck engine w the vortecs and an Edelbrock manifold on regular gas in my C20.
 
9.5:1 is generally still fine with low octane gas, these heads were stock on 350's that's spec'd out 85/87 octane and their stock compression was similar.

If you're sticking with the engine you have, the Vortecs are a good option. Way better than what you have. There are tons of good aftermarket options too, but a little more $.

The center bolt valve covers and newer intake design are way better all around too.
 
Be aware, if you're using anything other than a stock cam you'll need new springs and clearance checks for valve/piston.
 
I got my Vortec kit from Scoggin Dickey years ago, then they were good up to,.460 lift, have they changed?
 
76zimmer said:
I got my Vortec kit from Scoggin Dickey years ago, then they were good up to,.460 lift, have they changed?
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Not unless you get an aftermarket vortec head. Stock ones start pushing studs and having coil issues past .450”
 
This was about 2000 when I got a kit from SD Chevrolet. Their ad said up to .460?
My cam was .454
 
A lot of people run the vortecs. But if I remember right, they have a tendency to crack. It's really their only downfall besides the lift limit.
 
Change the springs and retainers and you can get .500+ lift.
Machine the guides and spring pockets for more.
 
I ran that lift on my 350 because it was a tow truck and I didn’t want to have any machine work done for anything bigger.
the vortecs require the guides and spring pockets to be machined, and larger springs for anything more than that.
 
shady said:
A lot of people run the vortecs. But if I remember right, they have a tendency to crack. It's really their only downfall besides the lift limit.
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There's 2 casting numbers. I forget exactly what they were, but the "good" one (truck head) has sawtooth casting marks on the end.
 
I run EQ-350 Vortec heads from Engine Quest. Much thicker casting than the GM Vortecs. Also the Dart Vortecs are thicker. The EQ-350 advertised 64cc. I measured them and they were closer to 67cc. Milled .020 off the EQ350s. Would be very careful with used GM Vortecs. In my years, I have found very very few that were not cracked. Use an online compression calculator. Pistons should be just at block deck plane. Then a .038-041 gasket, and you will get better power and mileage.
 
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