[Jay S]

Originally Posted by 77 TRASHCAN

Jay, I have one of those Crane cams, for use in a 455. How does it differ?
Jeff

The Crane version has a lot of seat timing like the SPC-8 but also has Asymmetric closing and opening ramps. The other RA4 type cams are closer to symmetrical profiles. I am not sure if Crane did that on their own to try to update the old profile or if it is something they copied from an original 041 cam. I have not been around the Crane version, I have only seen Cam DR files of it.

[scott70]

Originally Posted by RallyBird

Looking to build a .040 over 428 motor. Going into a 1967 Firebird, TKO 600 with .64 OD, 3.73 gears on 26.3 inch tires. Decided on the 60919 cam, as I already have one. It will have forged pistons, rods and crankshaft (3" main, 4" stroke). Heads are SD Performance prepped #62's that flow 250 @ .550 lift, 1.7 installed hight with Crower 68405 springs. Intake is an early 1971 HO, and I will be running a Q-jet and long branch manifolds. I will be running 93 octane, but it needs to work on 91 octane (just in case). I still need to pick my pistons. What compression should I be building this motor to. This is a street car. I should add that it will be zero deck, .039 head gasket, Rhoads V max lifters and Crower 1.65 roller rockers.
Thanks in advance.
Peter

What did your 62 heads cc at? A set that I had were 77 cc.

[Cliff R]

The "old" version of the 60919 cam is a SPC-8 from CMC. Crower simply "juggled" the numbers to make it look like their own cam.

Tey were NOT on a 112LSA, nor were they shorter seat timing.

Crowers on-line catalog clearing stated they were 112LSA but the cam card that showed up with them said 113. The cam card also listed 304/316 advertised, and 231/240 @ .050" with .470" lift using 1.5 rocker arms.

I'd also note here that if you installed it "dot to dot" it was not anywhere near 109 ICL, closer to 112-113 instead. I used to advance ALL of the ones we installed to get them to 109ICL as recommended on the cam card.

So Crower, like just about every other cam company out there simply bought them directly from CMC, juggled the numbers a bit and sold them as their own grind. That has been going on ever since I got into this hobby BTW.

Just look at the SBC "RV" cam, 204/214/112LSA. It is and has been sold under at least a dozen different labels by every cam company out there and is and always has been the SAME cam bought from CMC and "re-boxed" and re-sold as their own grind.

The Pontiac 224/234/114 cam has the same history, currently sold as the Summit 2802, and was sold by just about everyone else out there at some point with all of them calling it their own grind.

Since I haven't bought a Crower 60919 for at least 10 years now they may have changed it up at some point (disclaimer to my above statement).

As for 60405 valve springs they will test closer to 125-130lbs on the seat depending on which retianer you put on them. They are EXCELLENT parts and KRE used them on their aluminum heads for many years and may still be using them unless they are set up for something "special" for the end user.

When I was building these engines the 68404 (1.6" installed height) and the 68405 (1.7" installed height) were the "go-to" springs I used on Pontiac iron heads. In almost all cases I ran stock retainers on them and never had any issues with knocking cams flat or high RPM issues. Matter of fact I ran my first set of KRE heads with the 68405's for many years with the 60919 cam and 1.71 ratio rockers on them. When I decided to " freshen up" that engine I had another set ready to install but all the springs tested right on the money for seat and open pressure so I left them in service until I replaced that engine with a more powerful one.......

[Jay S]

Originally Posted by RallyBird

I will look at it. I picked up these heads off the internet. They were run long enough for a cam to go south during initial start up. Previous owner sold them and went to aluminum. That is the way they were set up. any recommendations. I do have another set of heads prepped by SD Performance. They are a set of 670's that flow better, other then the .100 intake flow, where they are less (79.7 vs. 90.0). I was saving them for a 455 build. They are converted to 45 degree intake seat angle, and have 995 springs also installed at 1.7. Is that any better ?

Depends….The 45* seats on the intakes move more flow to where the piston speed is faster. The engine scavenges less, if your not careful it will make less power. It is similar to widening the LSA of the cam out 2*, often an engine will drop HP with that change. For 45* intakes best results are go change the cam (narrow the LSA) or add about a half of point of static compression. I run 11.3 SCR on 91 pump gas with 45* seat and a good sized cam with 6X heads. They flow close to 300 intake and 220 exh. For valves it has 2.125” intake 45* valves and bigger 1.77 exh valves. Many times people attribute the gains in compression to be solely from aluminum heads displacing heat, I don’t think that is the case. Most of the extra compression people are able to add going aluminum is coming from how the heads flow, increased port volume and the change in air velocity thru the head, it is filling the cylinders where there is more piston speed.

[Jay S]

I think all you would have to do to see which 60919 you have is to set it next to the SPC-8 and compare the lobe widths. If it has narrower lobes if is the later 60919. If it has the same width lobes it is what Cliff ran.

[Stan Weiss]

The Crane cam data came from Ken Crocie / HO Enterprises and the test was done about 35 years ago. The Crower data is more current but I don't remember where I got it.

Stan

[RallyBird]

Post #24/25. Comparing to Edelbrock cam, SPC8 not available to check. Crower and Edelbrock cam are on the same cam core but ground different. Crower cam ground on a smaller cam lobe with a corresponding shorter lift then the Edelbrock cam. Only identifier on the Edelbrock cam was 9Z002. Lobe actual width's are approx. the same. Sounds like the 670 heads with the 45 intake seats I should be using on the 455 build, with the 041 cam and another half point compression.

[RallyBird]

Post #23. I plan on the Crower cam for the 428 build. I have three of these style cams and plan on using them. There is probably better, but I have these are on hand and they are paid for. Crower site specs. that cam for 428/455 builds and recommends 10:25 compression, and Summit lists as 9:5 minimum. If you were building this combination Cliff, what compression would you build to. I was thinking 10:25 myself. Car is not overly heavy and has a good rear gear with only 26" tires. The only thing that worries me a little is the OD ratio being only 2.39 final. Did not want to go with more gear because of the first gear ratio. I will be reaching out for a Q-jet rebuild shortly.

[Cliff R]

At least 10 to 1, wouldn't hurt my feelings if it came out a little higher.

My own 455 with 6X-4 heads was right at 9.97 to 1 and EASILY managed pump gas, even 89 octane and never grumbled much. Tunning 92-93 didn't help it at the track or make any noticable difference anyplace. This told me it could have used a little more compression and been fine with it........

[Jay S]

FWIW..The 428 will like the 60919s narrower 112 LSA and the 670 heads with the 45* seats will like the 60919s shorter seat timing. Of the combination of parts you have that will give the 428 the most grunt to pull tall gears. The SPC-8 likes the 62s 30* intake valves and wider LSA in a 455.

[RallyBird]

Thanks for all the great responses. Just finished measuring all the combustion chambers, came in at 74.675 and 74.775 for an average of 74.725, LOL. Now I have o go through all the posts and do some evaluating. I am definitely ordering my combo tomorrow with the DSS 14cc dish 4032 pistons. I was hoping that somehow, I could have pulled of the 7cc dish flat tops with the 670's. I will update as soon as I have looked at all the options. More are welcome.

Regards,

[RallyBird]

Post #30. Just finished up some compression calculations. I added 2cc to the piston dish for valve scallops and volume above top ring. Read on this site that is usually missed, makes sense to me, as I would not have considered it. So, the 428 with the 670 heads and the 60919 cam comes in at approx. 9.75. That set of heads is set up with Comp 995 springs (any issues there). I do want to run Rhoads lifters (V pro street with super lube), mostly for cruising in OD and as an aid in cam break in. I do like the adjustability with these lifters, and I have had a very positive experience with this company. Would that be an issue with this combination. The 455 with the SPC-8 and the 62s comes in at 10.25, and I do like the sounds of that. 2.64 ST10 and 3.23 gears. I will definitely run the Rhoads with that combo. That is for a future build, spare or possibly another Pontiac, as I do have room in my stable. Ordered my rotating assemble today. Thanks for all the input. Nowhere near knowledgeable enough to pick a cam and corresponding compression on my own. The only one I picked last did not perform as I expected.

Regards,

Peter

[Jay S]

If the 995 springs are too spec and set up correctly they will work fine. If those heads cam from SD performance I think he would have checked their pressures.

The Vpro or Vmax lifters will definetly give you some tuning flexibility on the overdrive.

With the 428 set up how your describing it very likely could be tuned to run on 87 octane. The 455 will like 91. You probably could have went with the flat top on the DSS piston with the 7 cc valve reliefs and ran on 91 on the 428 combo with the 670s and 60919. But, IMHO that extra squeeze is really not worth it. An extra 7 cc with the 14cc dish really won’t loose much power. The DSS pistons are down in the hole quite a ways, usually have to deck the block or run a thinner (.027” cometic) head gaskets to get a decent quench. I’d shoot for .035” to 055” for quench. My pump gas pontiacs are all in that quench range.

[RallyBird]

Post#33 Update. Decided to change to the 7cc flat top piston, with the 670 heads. The sale tech. at Molnar had no issue changing my order. I do like the sounds of a little higher compression, and will be running 93 octane fuel. I am no expert, but a flat top with the 670 head combustion chamber should have very good quench. I will be decking the block flush and ending up around .039 for quench. My compression should be around 10.3 to 10.4 range. Sounds like it could be tuned to work. Spoke with Cliff, who will be helping out with my Q jet rebuild and tuning. If this compression range is a little much for the 428 with the 60919 cam, what would be a good pick. I do have a couple of options for the 60919 cam, possibly a higher compression 400 combo. I was thinking about the 60243 cam, but sounds like the 60919 can be made to work.

[Jay S]

Originally Posted by RallyBird

Post#33 Update. Decided to change to the 7cc flat top piston, with the 670 heads. The sale tech. at Molnar had no issue changing my order. I do like the sounds of a little higher compression, and will be running 93 octane fuel. I am no expert, but a flat top with the 670 head combustion chamber should have very good quench. I will be decking the block flush and ending up around .039 for quench. My compression should be around 10.3 to 10.4 range. Sounds like it could be tuned to work. Spoke with Cliff, who will be helping out with my Q jet rebuild and tuning..

Good plan.