His is a flat tappet hydraulic cam. Also, I suggested that he get the spring pressures from Edelbrock and run them by Crane for the final say so.
No arguement that roller cams require greater pressures than flat cams, due to the quicker opening rate, but the .550" lift rating on the springs installed in the heads you bought, were a "coil bind" limit, not a spring pressure capability limit. Exceed the lift limit of an assembled head, and you'll have much greater problems than valve float. That same spring could have been installed at a greater installed height, to increase "max lift", but it would have had even less pressure, across the board. Ensuring that the springs (as installed) will handle the lift of the cam you are using is only PART of your job.
Indeed, you would have. The pressures were not high enough for your agressive cam. But those springs DID allow for the amount of lift you were installing. As you have very eloquently explained, lift capability is not the ONLY thing to look at in the purchase of heads.

Outlaw1984,
Be aware that these pistons are rated with a 64 cc head. Make the appropriate adjustments for your 70 cc heads. Good luck, and...

RACE ON!!!
1984 Crossfire
Member NHRA


[Modified by CFI-EFI, 3:02 PM 7/6/2003]

 

Thanks much CFI-EFI...

 

HEY 84-ER'S
My first engine rebuild is a 1984 Corvette, and its going great! The block is stock has crossfire injection air delete belt. I have had it for a week now and the block is bare besides the oil pan/crank shaft/cam/pistons. I recovered the Vet from a flood in FL Hurricane Ian. Lots of thanks to the high door wells the water did no damage interiorly. The engine 114,000 odometer is electrically sound, but the water found a way through the ports of the cut exhaust and well you could say the engine seized right away "dealer states". I have never owned the beautiful things one week and already drained all the fluids; the differential was dark but the only thing i believed was sealed. The air filter looked dirty but so was the motor to be honest. After a while I cleaned the parts looking great again i made some progress. The dismantling was great and a living representation of craftsman ingenuity. I have the motor in "soak mode" in oil. My components are flawless and no issues to come i hope. I have the cylinders open with Mystery Oil in them. The best idea i have is to use a block of wood and wack them free. Automatic transmission so i can't rock it, (right?). I also think the bolt for the crank pulley is too small to try and break it loose (any ideas?). The starter ticks but, sometime, and i think it will free up a little atleast before i inspect further into pulling the motor and pistons/arms. Any tips on all the gaskets replacements/bolts or upgrades? I Hope to be on the road in the "lifesaver" i'm calling it for now but once it's revived referred to as the hurricane, "survivor". Yaaa coolest thing in the world!

 

This thread is nineteen years old. Time to start a new thread.