Doh! Just realised that this is concerning an L series engine.

Disregard, the cam tunnel comment and rocker ratio comment.

With that sort of duration you can run a pretty high static compression ratio as the valve overlap will drop the effective compression ratio. A high compression ratio also means a higher suction to draw the air/fuel mix into the chamber.

That lift figure would have to be at the valve. You would be hard pressed to fit the cam in the tunnel otherwise. Unless the base circles are ground right back.

If you are just after a rough idle, just pull the choke out! or close the points gap. . .

The higher the lift, the more radical the angles on the rocker gear, the more wear.

Try something with a more conservative lift and if you want more out of it latter, put a set of higher ratio rockers in.

If you are just after a rough idle, just pull the choke out! or close the points gap. . .

the rpm range is 4500-9500....its a full race cam...the reason i want to use that cam is because of the heads it will turn....the heavyidle will scare people...any way i thought about it and i might just go with a .540 kit...which is a raddy street cam..duration is .292...around there...i hope i still get that killer characteristics of a full race cam...well the sound and lummpyness... what do u guys think....
has anyone used a high lift cam...how was it????

I think it must be a badly mismatched kit for your use then.

That much lift must have very long duration or the valve acceleration rates would be too high.

I would think the cam would have 280 degrees at .050' lift! This cam would be a 6000 rpm plus only cam. Who made the decision on this cam

the cam i'm planning on ordering comes as a kit w/valves springs,retainers,etc...so i will not run into problems i think???

I have found that on fuel injected engines that premium ULP paid for itself in better economy & more power. I know this is because the computer alters the timing etc but surely there are similar benefits with careful tuning. I am particularly interested as I want to get the most of of my next engine & don't really want to compromise on fuel.

That kind of lift will pose difficulties with valves springs, and retainer to guide clearance I think.

if you're building such a serious engine, why are you only going to use horrible LRP fuel?

9.5:1 is the maximum you want to run on pump gas, well that's what I have been told, and thats what my A15 will be running at.

the reason i'm going with the forged pistons is for the big cam i'm puting in...Lift=.592....the cast stock ones wont clear.....and i'm planning on running at least 150 shot nitrous...what do u think???

it depends on a few other factors, but yes on low octane LRP it would be best to keep compression down under 10:1. You can easily get this compression with cast replacement pistions and they will be more than up to the job. Spend the $800 dollars you save from the forgies on other stuff that will actually make it go harder.