Edelbrock with t&d, new cam choice

[427fordman]

Been a long time since I've been here. I'm putting my 462 back together this winter. It's a 12:1 Edelbrock head with Blair Patrick valve job, fully ported. 1100 dominator on a Victor. Cross bolted 428 block, .030 over with a steel crank and Manley h beams. 3000 lb Fairlane with a power glide, 5000 coan converter. Now I run an older comp solid roller, close to 20 years old. .686 .644 lift, .266 .276 @ .050 duration. I'm thinking I would get a new cam as I'm putting a set of t&d rockers on so I need new push rods anyway, might as well update the whole valve train. I talked with lunati, they are talking a .735 lift intake and exhaust, .268 .274 duration @ .050 on a 108 or 110. I filled out a form on bullet website but no response

Couple questions. What rocker is the correct one for the t&d race rockers for the Edelbrock? Another, what do you think of the cam suggestion from lunati? Also, I suppose I just block the head oil passage to the rockers as the t&d oil through to the pushrods?

4.30 gears, 29x11 tires. Has a trans brake, but I foot brake at about 2500. 1/4 mile drag only car. Best pass with the old cam and 4.11s was 10.03 and it weighed 150 lbs more then. I've put a new a arm front suspension on since then and set the motor back 9 1/2 inches. That motor was 6500 shift and through the lights, looking for 6800-7000 max. The old motor was 667 hp, 630 tq.

[blykins]

My first question (and the question everyone should be asking) is what do the heads flow?

[427fordman]

These numbers are on Blair's flow bench.

.100 91
.200 167
.300 224
.400 273
.500 297
.600 312
.700 312
.800 312

For what it's worth the guy who originally ported them, his flow bench showed 330 @ .700 before Blair got them and did his valve job.  Blair's only showed 305 @ .700 before.  Difference in benches, or operators, or combination of both.  After his valve job the lower lift numbers improved a lot more, over 20 cfm @ .400-.600

[blykins]

That's common, some flow benches show different, just like some dynos show different. 

You're wanting a 6500 rpm peak with a 7000 rpm shift point? 

[427fordman]

I'm looking for 6800-7000 shift, same through the traps.

[blykins]

So Blair picked the heads up quite a bit, which makes it easier for the cam to do its job.  You don't have to hold the valves open as long, since the heads are more efficient at getting stuff through the door. 

You don't need more duration than your previous cam as the heads will let the engine pull several hundred rpm higher. 

Do you have exhaust flow numbers as well?  I should have asked for those earlier. 

To answer your other questions, T&D 7030 would be the part number you need for the paired race rockers.  They are pushrod oil only, so yes, you block off the feed to the heads.  Depending on the lifters you have, you may even have to run a restricted pushrod.  If you weren't aware, the heads have to be cut to use these rockers as they use a common bar that's head to the head using the head bolts/studs.  You will see why you have to block off the feed to the heads after they are cut for the T&D stuff. 

[427fordman]

I don't have the exhaust numbers in front of me, I'd have to do some digging.  I don't remember getting them from Blair, but maybe I did.

Anyway, bullet got back to me today.  They recommend close to the same as lunati did.  The one they say is .272/.280 @ .050, .748/.742 lift.  LSA 108, degreed at 104 for IC.

Thanks for your help Brent.

[blykins]

I certainly wouldn't go that high on duration.   A 6800-7000 rpm shift point is, in the overall scheme of things, fairly low. 

The last two 465 inch bracket engines that I've done have been in the +/- 700 hp range.  Both of those engines peaked at 7000-7200 rpm with 260/270 @ .050" duration, but the heads were really good on both engines.  I suspect that your heads will perform similarly.   

Adding 10+ degrees of duration will only raise the peak hp rpm higher when the cylinder head is capable of supporting it. 

Any cam company that you're getting a recommendation from should be asking you about 50 different questions, including flow numbers on both the intake and exhaust sides.   The exhaust flow numbers help dictate the amount of overlap/spread that you need.  No one has mentioned advertised durations either, which are just as important as they dictate how aggressive the lobes are and how much overlap the cam has. 

Sometimes the lobes are such that the overlap is WAY more than what's needed.  A guy came to me asking for a camshaft for a 377 inch Cleveland.  He was running a Crower shelf cam with about 90 degrees of overlap.  I ground a cam for him and kept the hp peak rpm the same but decreased the overlap by widening the LSA up.  I picked that car up a tenth in the 1/8th mile.   

[427fordman]

I was asked a lot of questions by both companies, but neither asked the exhaust flow, and neither told me the advertised duration.  Granted both of these were online forms I filled out, I'm sure if I call I can get the advertised duration, and maybe they would ask for the exhaust flow? 

I guess I have some more thinking to do.  I really enjoy building these motors, but cam design is not my best area. 

[fekbmax]

I'd let Brent or Blair have a custom cam ground for you. You will get the best cam for your combo hands down . My last several race engines I always had Jim Kuntz (rip) do my cams as he always wanted to know everything about the combo. I'll for sure let one of the guys above handle my next cam selection.  JMO.

[afret]

n/m

[CaptCobrajet]

You will need ballpark 270s at .050 to get a 4.250 stroker to peak where you want to, with the port cross-section and manifold you are dealing with.  The strokers gobble up camshaft.  I sent you a PM.

[blykins]

I suppose I'll ask for clarification.  Has the combo been ran with the cylinder head modifications?  Or were the heads ported while the engine was down?   I've been assuming the whole time that you had head work done while the engine was down and you've been wanting to know if you need a new cam. 

If the scenario you posted was with Blair's head work, then I would agree, you may need to add some more camshaft or do some fiddling. 

If the scenario you posted was not with Blair's head work, then IMO, I'd stick the old cam back in and try it, unless you're just really jonesing for something new.  Additional head flow adds peak hp rpm and you're not too far off from where you want to be.

[My427stang]

****ON EDIT...great minds think alike LOL******

I am going to jump in here and ask another question, were the heads recently ported and now you want a cam to pull a little more RPM?   or has this combo been together and now you just want a little more RPM?  It's unclear to me

Also, what RPM did it peak before?

If it's the first option and you have new better heads, unless the heads gave up something somewhere else that is making you think they don't work well, I would be very careful about adding too much cam with a 462.  The heads will carry.  I like Brent's idea in that situation and I would be very careful on lobe selection too, it makes as much of a difference as the standard .050 and lift numbers, especially with stability upstairs.  In fact, if you have better heads, I'd likely tight lash and see what it does

If it's the second option, and the heads are unchanged from the prior season, then I wouldn't think you need a lot more cam, but again you could rock it back a little and lash it a little tighter if the lobe allows. Depending on the current lobe and lash you may gain a little with just tuning, maybe not enough, but you aren't asking for a lot (depending on where it peaked before)

[427fordman]

Thanks everyone.  The heads were done a few years ago and ran with the old cam.  I should have been more clear on that, sorry. 
I will get in touch with the guys here and get a cam, lifters, and rockers at the least.