yeh.. with the big intake valves and stock pistons, how big a cam can i go?

was hoping for .512 valve lift(with 1.6 rockers) with 218 duration(measured at 50 thou) and 224 duration for exhaust.. i know stock cam is .444 lift but i forget the duration.. was possibly looking at a cam with 224/232 int/exh dur. and 555/565 valve lift to run with stroker, but putting that in now, will that be too big?

i am also asking the question of - is it worth testing? or will it just simply not work?

ah just found article here http://www.carcraft.com/techarticles/116_0111_build/

that says these bits-

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We were surprised to find how big the stock 5.0L cam was, measuring 208/212 degrees at 0.050-inch lift, with 0.445/0.445-inch lift at the valve with the stock 1.6:1 stamped rockers. With 218/228 degrees of duration at 0.050, the Lunati cam is not radically bigger, but it provides much greater lift--0.536/0.536.

Holley warns in the instructions that p-to-v must be checked with the large 2.02-inch intake valves in the Holley Street Avenger heads and the bigger Lunati cam. We rigged up a dial indicator with a set of lightweight checking springs, and using the degree wheel, checked p-to-v clearance. Sure enough, while we had plenty of clearance on the exhaust side, the intakes were tight, with just 0.030-inch clearance without a gasket. Assuming a 0.039-inch-thick head gasket, we might have barely squeaked by with a clearance of about 0.070 inch, but 0.080 is closer to a comfortable minimum.

Since we already had the pistons out of the block for cleaning, it was easy to run a Dremel tool with a cylindrical-end cutter bit along the edge of each intake relief to lay back the rear of the notch slightly. We removed a minor amount of material to allow the valves to travel into the pockets without hitting the edge of each relief. Most aftermarket performance pistons are designed with notches large enough to accommodate the big valve heads, so this could have been avoided had we opted to bore the block and replace the pistons from the start.

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sooo even tho they opened up the valve releifs a bit, i think ill give it a go.. ive got a spare 5.0 in the shed im selling so i mite crak the heads off it, whack the big 2.02 valved heads on, n at least see how much clearance i get with the stock cam..

just bolt em on with play doh on top of the pistons, but you need around .100'' of p to v clearance, to be safe at higher rpm

It depends on what heads you're running as well, aftermarket heads have different valve positions. For example TFS Twisted Wedge heads (2.06" Inlet valves) will fit on a stock 5.0 bottom end, and run around .530" lift with no clearance issues.

I have the flow figures for the GT40P heads but not the valve sizes. Does anyone know what they are?

1.84"/1.48" sounds familiar....

http://www.thatmetalbox.com/automotive/ ... d_flow.pdf

^ good chart

Isn't it interesting how the intake flow starts to drop off at around .400 and .500 and plateau's wheras the exhaust flow keeps climbing reasonably evenly till .600 ?

if you check out the cam specs for GT40p equipped engines, you will find that the lift is much less than the E series with E7's ,I have also read by several engine builders " by fitting larger valves to these heads you will reduce the high lift flow figures quite dramaticly & if used in conjunction with high lift/duration cams powerband will be later in the range , and be shorter"
this is compared to porting and replacing the valves with
higher quallity stainless items, it also refers to E7's being
very similar in behaviour?

im not retro fitting big valves into the e7s.. im actually bolting on edelbrock performers..