There is more to spring selection than just lift capacity.
The XFI lobes are fairly aggressive and a dual spring with the "right" seat pressure has a lot more weight to handle than the beehive springs Comp envisioned when they designed the XFI lobes which can mean the valve bounces off the seat when it closes at higher rpm, that and you are going to have to turn this MUCH higher than the 6200rpm Comp's literature suggests. It probably wont even peak by then and you need to rev past peak. Expect to need 6800+rpm if those heads actually work well.

I have tried a few different ignition things over the years and bone stock opti/coil with no ignition box is how my car has been fastest. Plenty of us have made the mistakes there is no need for the newbies to repeat them. First thing I bought for my car was $400 worth of ignition garbage that in the end only caused problems and I threw parts at it trying to figure out what was wrong wasting more money till I took the ignition "upgrades" off.

 

heard, thank you when i bought the cam it came with its own spring would it have been better to take the ones off the heads and put those on, i suggested that and my father told me i didnt want to start taking my heads apart.. all it told me about the valve spring was the outside diameter is 1.055 in.

 

There are those who will argue but IMO the 918 spring Comp recommends is insufficient because the 6200rpm Comp says it needs is wrong, more rpm means more spring is needed.

 

IMO?. that is one thing that i wish i would of known the motors already back in are those spring going to put any of the parts of my car in danger.

 

imo=in my opinion

 

Befor the motor went in.
After it was in

 

The springs wont break quickly but the power will nosedive suddenly at higher rpm when the valves float.

Those valve covers are absurd, 5 minutes(less the second time you do it) with tin snips makes the stock valvecovers fit even wide body roller rockers.

The Bosch box makes me ask but I can't tell what it was for. You didn't put Bosch plugs in did you? What plugs did you use and what is the compression?

 

heard yea they made putting it in a pain in the *** i just thought there were issues with the rocker rollers hitting them, those are the ones we put in my dad said that with the blaster coil and msd box that i would be getting hot enough fire i was going to get the ngk. the compression is 11 to 1.

 

i had the ngk iridium in there before

 

By 96 the idle emissions standards and 100K mile tuneup interval meant the ignition was quite "hot" bone stock.
Listening to people who "learned" how to mod an engine in the 70s is a sure way to fail.

My Dad was into cars when I was a kid, he lives a distance away from me now though so we don't do any of that together. He finds my car amazing because it breaks all the rules he knows. The one that shocks him the most is I get better mileage with a mid 11 second Caprice than he and I do our daily driver fullsize pickups. He has a hard time believing you can get economy like that with this kind of power.

11:1 is low for an NA LT1, most heads/cam cars use a thin gasket and endup higher than that, most built LT1s are 11.5-12.5 on pumpgas.

 

, thats no bueno. again thats what my padre told me how do u test it or is it just combining everything u add???