[Steve C.]

"I bet in Powells opinion the Pontiac exhaust is choked, probably compared to other cylinder heads."

X2

Related: NOTE the revised exhaust port design on Paul Kinippen's new Edelbrock cylinder heads.

[scott70]

Is a iron D port head that’s been ported using rare oversized iron manifolds and a 3” head pipe a good candidate for a 236/242 hr cam or would you want a little more exhaust duration?

[Skip Fix]

With good exhaust the old HO Racing guys recommended a single pattern for ported D ports!
I think the exhaust manifolds would warrant a "regular" split pattern.

[Steve C.]

A good read...

Bad exhaust ports?
https://forums.maxperformanceinc.com...d.php?t=820491

And a tidbit that might be of interest.....

A statement in that thread linked above by Cliff Ruggles...
"To be the devils advocate again there is a LOT more to this port flow deal than can be measured on a flow bench."
He goes on to elaborate, but that statement rang a bell.

I know they are not apples-to-apples with factory d-ports in this thread, but in my recent conversation with Paul Knippen regarding his revised Edelbrock exhaust port he mentioned a similar situation as Cliff brings up.
How his exhaust ports "behaved" on the flow bench, and not related to the numbers obtained.

Memories, my old engine builder years ago used to "listen" to his flow bench.

.

[Skippy597]

That was a good thread to read.

I still feel the round port after market heads definitely have sufficient int to ex ratio.

I'm leaning pretty heavy towards to butler custom grind 239/247 113lsa. Does anyone think I'll have issues with power brakes and a/c.?

[Jay S]

Originally Posted by Skippy597

That was a good thread to read.

I still feel the round port after market heads definitely have sufficient int to ex ratio.

I'm leaning pretty heavy towards to butler custom grind 239/247 113lsa. Does anyone think I'll have issues with power brakes and a/c.?

Unless has something different than the stock booster I think power brakes would be a little sketchy in an early A body with Bulter’s cam. Would work ok with a gen 2 F body power brake set up or possible a different booster than stock on the early A. I am assume this is going in a 66 A body?

[Skippy597]

Called bullet, Tim was still unavailable so I spoke to another tech. And I like his recommendation.
236/244 @ .050
582/582 lift with 1.65 rockers
112 lsa

Seems very close to the comp and just different enough. I'll be ordering it soon I think.

[Jay S]

Originally Posted by Skippy597

Called bullet, Tim was still unavailable so I spoke to another tech. And I like his recommendation.
236/244 @ .050
582/582 lift with 1.65 rockers
112 lsa

Seems very close to the comp and just different enough. I'll be ordering it soon I think.

I was going to mention you don’t have to talk to Tim, he trained a lot of the other guys working there. That is likely the cam Tim would have picked also. It is quite a bit easier on the valve terrain than a XR236/242 comp, better valve control, and operates quieter also. It is more like the Butler custom cam but with less lift, which you really won’t miss.

[scott70]

These are some of the questions I might have also. Pulling my motor out soon for some things and currently run a hft cam. The last one was a 60919 and showed signs of a couple of lifters that weren’t spinning correctly so I had a custom crower ground and used rhoads lifters again. If I find any of the lifters that show signs of not spinning again when I pull the motor out I will be switching to a hydraulic roller and that custom cam you just mentioned is something I might go for.

[Steve C.]

The Bullet lobes appear to be HR290/3533 and HR298/3533

https://www.bulletcams.com/Masters/HRlobes.htm

290
236
156
.3533

298
244
163
.3533



.

[Jay S]

One of the guys on the forum, just over 10:1 461 with stock E heads and the 60311 with 1.5 rockers.

On my old cars I pick mechanical SFT and SR cams over hydraulic flat tappets and HR’s most of the time.

[Skippy597]

Yes I am running Harland sharps and I was expecting that. They (Harland Sharp) even told me they measure above 1.65 ratio.

I think its actually perfect with that extra boost of lift. But it's not a bad idea about the slower exhaust. I'll talk to them about it when I order it.

[ponjohn]

Is everyone still keen on the Johnson short trvel lifters?

[Skippy597]

You had to bring up lifters. Lol

Man, I hate to admit it but I think I'm going with morels... I think. The comp evolutions still look nice but they have moved up in price.

[JLMounce]

I'm running Johnson Short Travels on my QNI lobed cam. No hint of valve float even at 6000 rpm and they are quiet.

[Skippy597]

So after being sold on doing a hydraulic roller from butler and comp evolution lifters. The budget has been getting pretty high and I already have a set of NOS johnson solid flat tappets with the edm oiling hole. So I'm thinking it might just be best to run a SFT cam.

I was looking at the crower 60311 and have rea don here a lot about it and a many guys suggest it is equivalent to a RAIV cam. I also contacted crower for a custom cam and they gave me one that's just a hair more. Here's the grinds


#00160M CUSTOM 400/455/460 PONTIAC SOLID FLAT....112 LSA 250/256@050".....348/.354 LOBE....522"/.531" GROSS W 1.5RR....B1317/B1318


Crower 60311
INT/EXH - Dur @ .050” Lift: 247°/252° RR: 1.5/1.5 Gross Lift: .505”/.517” LSA: 112°


My concern is would these cams want to run in a higher rpm than I really want to? I think I'm going to set my limit at 6000 and want to make sure I'll make good power off idle.

[steve25]

It’s a near wash.

The narrower 112 from the RA4 cam will bring down the power band while making the idle sound even more nasty.
The added duration will bring the power band back up higher.

[Skippy597]

Noted, thanks Steve

[Lee]

Note the cam in my '67, in my signature. It was a SFT from Bullet, using UltraDyne lobes. 247/247 @ 0.050, 108lsa 109icl. In the .060 over 455 I had, that motor ran best shifting at 5900rpm (and I crossed the finish line at 5700). That cam gave up 60' time, compared to the HFT 231/239 @ .050 I had previously.

If I still had the car/motor and was putting in a new SFT, I'd probably drop about 8 degrees off of the intake and spread the LSA a bit more.

[Skippy597]

Originally Posted by Lee

Note the cam in my '67, in my signature. It was a SFT from Bullet, using UltraDyne lobes. 247/247 @ 0.050, 108lsa 109icl. In the .060 over 455 I had, that motor ran best shifting at 5900rpm (and I crossed the finish line at 5700). That cam gave up 60' time, compared to the HFT 231/239 @ .050 I had previously.

If I still had the car/motor and was putting in a new SFT, I'd probably drop about 8 degrees off of the intake and spread the LSA a bit more.

Thanks Lee. That's a big move to drop off 8 degrees on the intake side from what I've read everywhere is that would put it below a hydraulic Ram Air IV grind. I'm thinking with the increased exhaust duration and wider lsa than you ran 112 vs 108 I think it will be ok??? Maybe... I'm not sure but I think I'm gonna try the custom crower SFT cam. If it's terrible I can change it later it's not a big deal or big investment compared to a roller setup. I might loose lash it a hair to give the bottom end a boost.