[69camarox]

hi all I was wondering how well a set of 7f6 heads on a 400 with a 4.5 inch crank would perform and what cam you might recommend
stock 1968 block
4.5 eagle crank and rods
flat top forged pistons
stock 7f6 heads
long branch manifolds
1968 firebird
tko 600 trans
12 bolt 3.73
and 100% street driven

[steve25]

With stock 7F6 heads you should have between 420 and some 430 hp on tap with that added stroke.

I had a set of 7F6 heads some years back and I played around with valve jobs on them with my flow bench and I found that with a correct 2 angle valve job ( maxing out the OD of the 30 degree seat) with a deep 60 degree bottom cut got 240 cfm out of them which should net you maybe 450 hp if you get your Cam lift up to .525" and 232 Intake duration @ .050".
I think even a single patter Cam would serve you well with those heads if your not looking to squeeze out every last drop of HP.

I would shoot for a 9.2 compression for the build.

[ponyakr]

"...what cam you might recommend..."


With that many cubes, I wouldn't use anything smaller than an 041 clone.

With the stick trans, can probably go bigger & still be very streetable.

If you want a HFT cam, here are some slightly larger than the 041.

https://www.summitracing.com/parts/crn-284281

https://www.summitracing.com/parts/lun-10510507

http://www.pbm-erson.com/Catalog/Ers...t_E/ERSE310031

If you don't mind spending around $200 for a cam, you can go with a 60244 Crower, or just about any specs you want in a custom grind, including the old Ultradyne lobes.

KRE has the cheapest Crower prices I can find, depending on shipping charges.

http://www.krepower.com/Pontiac%20Ca...nd%20Parts.htm

Bullet can grind about anything you want.

http://www.bulletcams.com/Masters/Hlobes.htm

http://www.bulletcams.com/Masters/ultradynemasters.html

If you wanna maximize power, with a HFT, I assume you could go with a big Voodoo. But I'll leave that subject to Paul Carter & others.

Then, if you have another $1000 plus to spend on a cam set-up, you can go with a hydraulic roller.

https://butlerperformance.com/i-2936...tegory:1272239

https://butlerperformance.com/i-2936...tegory:1272239

KRE has similar cams shown as part numbers HR230 & HR236.

http://www.krepower.com/Pontiac%20Ca...nd%20Parts.htm

[69camarox]

I would probably go with a solid roller or hybrid setup as I have a set of solid rollers already and a set of 1.5 roller rockers and a set of 1.65 as well. I have the factory alum intake too. I am not too concerned with idle quality.

[Cliff R]

A HR cam would be a good choice. I'd look at the Road Paver from Dave at SD Performance, or something similar in seat timing/duration, lobe lift, etc, and have it done on a 114LSA and set the ICL at 109-110 degrees......Cliff

[69camarox]

so cliff with the road paver would the stock length valve work in the head or would you need a longer valve to get that .608 lift

[steve25]

It's longer valve time with the 71/72 round port HO heads to handle that much lift with a good long life spring package.

You will need to step up to the longer RA4 valve lenght and then check for the needed longer push Rods once all milling of the block deck and or head deck has been done.

[69camarox]

I am curious what you all think of a cam I already have. I posted a question about it in the race section . near as I can tell it is 278 282 @.050 .630 lift 110 lobe sep solid roller?

I am not opposed to buying another cam just curious how you think this might perform.

thanks bruce

[ponyakr]

"...100% street driven..."

Just wondering if a .600 lift cam is the best ticket for a street only car, or is that just trying not to "leave any power on the table" ?

http://www.sdperformance.com/viewPro...productID=1817

Not doubting the power a big cam will make. That's why race cars use 'em. Just questioning whether that much cam is what the OP needs, or would something a bit smaller be a little more street friendly, and possibly be a little easier on the rest of the valve train ? I don't have a clue.

[J.C.you]

If you want to use that cam you will need a 6000 series ferrea valve or equivalent and cam manufacturer recommended spring package. I would not go over a 1.5 rocker. Porting your heads/intake package would go along way in making your combo have some bite rather than a big bark with that cam.��

[Cliff R]

"so cliff with the road paver would the stock length valve work in the head or would you need a longer valve to get that .608 lift"

Difficult question. It's going to be more about the installed height you have and the valve springs being used.

I use and prefer higher installed heights with these engines as it opens up spring choices and give us more room to work with when going to "big" cams, like the .380 and .400" lobe rollers.......Cliff

[steve25]

You could cut the spring seats and shorten the valve guides to have up to .625" clearance , but you need new valves anyway in all likleyhood , and if you contemplating any type of Cam with that much lift then new longer valve are the safe and smart way to go!

[AG]

That is a stout cam for the street, it will need some compression. I'd go with 10.5:1 with iron heads and that cam. If your heads are 111 cc and bore is 4.155", you'll need an 9 cc dome. Flat tops with a 6 cc valve relief will get you about 9.3:1 CR.

[tom s]

That is a lot of duration for a true street car even with that stroke,with your trans you will be pulling it back a gear to keep it from bucking on you.I think Cliff has it right on the cam.Tom

[AG]

I made a mistake, compression will be 8.8 with a 4.155" bore x 4.5" stroke, 111 cc head chamber, 6 cc valve relief in piston, 1 cc deck, 9.3 cc gasket and 1.5 cc above top ring. If your head chamber is less than CR will be higher.

[69camarox]

bore will be 4.181 or 4.185. have to check pistons they are at work not set on that cam just happen to have it . and I am familiar with big roller cams I have a Camaro with 454 with .652 lift 262 duration@50 and I like how that runs

[AG]

CR will be 8.91 with a 4.185 bore and 111 cc head chamber, 495 ci. Big cam for the street. I'm going to run a CC 3123/3116 HR, 246/252 at 0.050", 0.400" lobe lift in my street 494 ci motor.