<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c2 width="75%">i put this cam in about three mounths ago but i left the stock valve springs in the d7oe heads at about 5500 rpms the moter sputters and backfires so i guess im floating the valves is there somthing i can install as a failsafe because ive already floated them like 5 times its hard to say im not going to do it again because some times when i down shift it happens i just dont want to blow this motor i was thinking rev limitor but what can i do with a mallory dual point dizzy converted to e spark . below are cam specs .thanks guys </TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Cam Style:</TD><TD class=overview-c2 width="75%">Hydraulic flat tappet</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Basic Operating RPM Range:</TD><TD class=overview-c2 width="75%">2,000-4,500 RPM</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Intake Duration at 050 inch Lift:</TD><TD class=overview-c2 width="75%">218</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Exhaust Duration at 050 inch Lift:</TD><TD class=overview-c2 width="75%">228</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Duration at 050 inch Lift:</TD><TD class=overview-c2 width="75%">218 int./228 exh.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Advertised Intake Duration:</TD><TD class=overview-c2 width="75%">276</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Advertised Exhaust Duration:</TD><TD class=overview-c2 width="75%">286</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Advertised Duration:</TD><TD class=overview-c2 width="75%">276 int./286 exh.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Intake Valve Lift with Factory Rocker Arm Ratio:</TD><TD class=overview-c2 width="75%">0.471 in.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Exhaust Valve Lift with Factory Rocker Arm Ratio:</TD><TD class=overview-c2 width="75%">0.471 in.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Valve Lift with Factory Rocker Arm Ratio:</TD><TD class=overview-c2 width="75%">0.471 int./0.471 exh. lift</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Lobe Separation (degrees):</TD><TD class=overview-c2 width="75%">114</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Intake Valve Lash:</TD><TD class=overview-c2 width="75%">0.000 in.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Exhaust Valve Lash:</TD><TD class=overview-c2 width="75%">0.000 in.</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #ffffff" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Computer Controlled Compatible:</TD><TD class=overview-c2 width="75%">No</TD></TR><TR onmouseover="this.style.backgroundColor='#f5f5f5'; " style="BACKGROUND-COLOR: #f5f5f5" onmouseout="this.style.backgroundColor='#FFFFFF'"> <TD class=overview-c1 width="25%">Quantity:</TD><TD class=overview-c2 width="75%">Sold individually.</TD></TR></TBODY></TABLE>

 

Ha.. yeah.. you need an ignition box with a rev limiter.

 

how does that box hook up and does it work with my dizzy

 

Get a Mallory or Autometer Tach with an adjustable rev limiter. I've had good luck with the Mallory tach's. Set it to around 5000rpm. Youve been lucky so far, eventially you could chuck a pushrod if your not careful.

 

get some springs, I thought you all ready had put springs in it, guess not............the motor will take 6500 all day long no need to limit it if you can't get there because the springs are weak old stock one...come on..........

 

Very true!!

 

the springs are the stock springs but they are new .will the cam pull to 6500 rpms where can i get double springs for d70e heads .the reason is i plan on getting new heads so i dont know if i should put money on springs unless its going to pull to 6500 rpms .i did not know a 302 could safley rev to 6500 with out forged rods ect .thanks guys

 

you don't need double springs, get some Edle. performer springs from Summit and you will be fine with that cam and they will fit on the D7OE heads............

and from what I have read the springs you get in some of those aftermarket heads are junk so you might as well be one step ahead of tthe game.

Myself and my brother have taken stock lower 302 to 6500 on a daily basis......but they had good valve train to get it there. You would be surprised how much a 302 can take, I have never lost a lower end..never.

When you change the cam to a performance cam you allways change the spring to match the cam......like bread and butter. Think I said this before.....

it might not pull to 6500 but a miss shift or broken driveshaft,u-joint will put it there.

I think it will shift at 5500 to 6000 with that cam.....

 

Just read your post. I feel a bit more confident in the 302 after reading your comments. I have a 68 block, 30 over, running Keith Black forged flat tops, Comp Cam K-kit (.493 intake, .500 exhaust), 72 heads, roller tip rockers, Edelbrock 600 cfm on Edelbrock Performer RPM, Ford magnetic trigger distributor and MDS 6A box. I have put about 2,000 miles on the motor since rebuild and have turned it to 5,200 once, 5,000 several times but have been hesitant to take it beyond that. You feel confident at 6500, huh? I'm using a C-4 and 9 inch in a 52 panel. (pictures in gallery)

 

Hey if it's still pulling let it go.

Whats the rpm range of the cam?

as long as it's making power and the valves are staying close...spin it. but if it's just making noise and no power........shift........

 

This may come as a surprise to you and some others, but you've already got forged rods. All you need is a good set of rod bolts to hold em together. If you've still got the stock or used bolts on those rods, that's the weak link, it's not the rod itself. The springs that your cam needs will be pushing the pressed in studs to the limit, you're liable to have a few pull out of the heads with stiffer springs.

 

only reason I did not mention screw in studs is Money.... he has none. lol


but I think if he gets the springs made for the cam 228 @ .050 they wont be stiff enough to pull the studs....my brother only started pulling studs when he went with dual springs. fun **** ...he would make a pass and come back to the pits with every rocker slamming. take a 3 pound hammer and slam them back down..make another run, and pound them back in. finaly got some srew in studs.

 

My 88 5.0 HO has seen 6200rpm uncountable amounts of time and never came apart. It still runs great @ 161,000 miles and holds 40psi oil pressure @2000rpm hot 20psi @ idle.

 

Different spring loads will create more or less pushrod/rocker deflection and you can loose lift. If your geometry is off you can loose lift. This is all static measurements though. When the engine runs the pushrod deflects more and you can loose more lift initially but the pushrod can act as a polevault and throw more lift on the valve and make it loft off the normal lift profile. It gets to be a very dynamic situation that changes alot at various speeds as parts come in and out of harmonics. Its easy to get 0.020 to 0.050 additional lift at different points of the curve. You loose it in others as well. Sorry if this is confusing but my first time watching the laser trace of a valve was very enlightening. I know why you need so much P-V clearance now.
If you're going to be turning high rpm's on a regular basis, you really need to consider lightening the valvetrain on the valve side of the rocker. Lighter retainers and valves make a tremendous difference. You should also seriously consider the beefiest, baddest pushrods that will fit your application. A thick wall, tapered pushrod is strongest. They're thicker in the middle, where deflection is greatest. This helps lessen the "polevault" effect. Insufficient spring pressures and lofting can cause the lifter roller to skid, rather than roll, when it comes back into contact with the cam. This will damage both the needle bearings in the roller, and the cam.
Don't ask me how I know, but I can tell you it ain't purty.


Pete

 

That is real good information, Pete. Thanks for sharing. My confidence level in the guys at USA Performance here in Pensacola who helped me with the parts selection just got even higher. There is some really good info in this forum. Thanks for sharing.

bernie