valve clearance ?

[351wStang]

im in the process of rebuilding my 351w. and im curious as to how much clearance do i need for a good streetable motor? like i said its a 351w, 5.8. bored .030", 3.5" stroke. im ordering edelbrock's performer rpm air gap intake and the performer rpm heads. a 750cfm speed demon. and comp has suggested a .546/.563 282/292 hydraulic roller cam. i have comps 1.6 roller rockers. the heads come with 2.02 intake, 1.60 exhaust valves and .575" max lift springs. im sure i will have to order new valve springs but how much more clearance do i need? i dont want to over work my cam. i will have roller cam, lifters, rockers, chain, full floating h-beam eagle rods and im looking at getting either wiseco or ross forged flat tops with valve releifs, hopefully get 10+:1 cr. any help with clearance values will be appreciated.

[MustangRoadRacer]

sounds good.
Victor Jr's would be my choice over the edelbrock heads though.
best bet is to check with the cam manufacturer about the springs and clearance issues.
they are VERY helpfull, and freindly people over at Comp.

[351wStang]

you dont think victor jr heads would be too much? wouldnt i have to find a cam and intake that makes more power at higher rpms to get full use out of those heads?

[SkylineUSA]

Here is the thing about cams. If you call 5 diffrerent cam companies, you are going to get 5 different cams.

If you are set on getting that cam, then Comp Cams should be able to help you on the info they give you.

You can always fly cut your own pistons, or have them fly cut so you have no issues.

It sounds like a killer engine though.

[MustangRoadRacer]

they aren't that crazy.
they are pretty cheap and have quality valvetrain compenents.
compared to some higher end heads, they are a little mild.
check out the latest MM&FF, they did a full test of a bunch of cylinder heads.

[351wStang]

ive been plugging in some #s on my desk top dyno 2000 and getting some good results. at 6500 rpms with the persormer rpm stats im puching about 574hp and 489'lbs at about 4000 rpms. im planning on running a c4 tranny with a 2800 stall and 3.73 gears with 27.5x12.0-15 tires. ive been told that i will loose around 18% of my power from my flywheel to my rear wheels. so i should be putting about 450hp on the ground. its been a while since i looked at the dyno so i dont remember exact numbers. but i think it will be one hell of a street car. i have a 4340 forged crank and im getting forged rods and pistons just incase i feel the need for nitrous sometime. ive been looking at zex lately for the just incase situation. thanks for the help and support guys.

[SkylineUSA]

Zex, is a good safe kit. I have one. Make sure you get a rmp window switch, that is what I use to activate it. I have seen some guys hit the N2O by mistake, BOOM!

Remote shut off would not hurt either, I run one of those as well.

[351wStang]

i talked to a friend of mine who just went to zex from and edelbrock nitrous system on his lt1 and he says its a little lower shot but he gets better results because zex is a wet injection where the edelbrock was a dry shot.

[SkylineUSA]

Zex is a dry kit as well. You only plumb in the N2O, there is no gas to plumb.

[351wStang]

i c, so like on the intake i have picked out at the moment which has nitrous bosses in each runner that just shoots n2o into the air/fuel mixture? and how do i figure out the stoichiometry of my combo? i assume the results with nitrous involved in the mixture is even more dependent on my air/fuel ratio? although i know i cant stay at 14.7 all the time or even at all with constant changes in the air.

[SkylineUSA]

You do not want to run 14.7 all the time. Any dry shot will have a fuel pressure sensor, to add fuel while your on N2O. The system will meter in the N2O.

N2O on each runner, so you are going to run a Direct Port then?

[GTStang]

Since you are building a carbed motor I would ignore Zex. I would just get a nice wet carb plate system for your engine like NOS or NitrousWorks. Carbed intakes work grea with wet systems unlike EFI intakes. I don't see a need to go with a Fogger unit unless your gonna run a 150+ HP shot.

[351wStang]

N2O on each runner, so you are going to run a Direct Port then?[/quote]
yes i was planning on going direct port, sorry i didnt specify before hand. and i doubt i'll be dealing with any more then about 125-150 shot. another question i had about n2o was scavenging with the cam. what kinda lobe sep do i need? something around 114? maybe 112?