Is anyone out there using either the Strike Force head, Superflow head, or Procomp head? I saw a thread that was briefly discussing the Procomp head, but I couldn't find any threads stating whether anyone was using them.

If you are using them, what kind of luck have you had with them and what kind of performance are you getting?

Thanks.

 

I have a pair of the superflow heads, the machining on them sucks. A local speed shop are going to be cleaning up mine.

 

Hey Guru,
I thought you liked your heads. I have a set and have talked about how crappy the machine work is from the very beginning. Mine are starting to look really pretty with all of the work I've done on them ,but who knows how they will flow.

 

So I take it that I should stay away from the Superflow heads unless I want to do some additional maching to them?

 

The Pro-Comp SB heads will support 450 HP on a hydraulic cammed 383 stroker, straight from the box with no porting. You have to remember the "dynamic" C.R. will be lower with aluminum heads than cast iron. You effectively lose a full point. This is the reason we are able to dyno 11:1 units, using aluminum on top, on 93 octane with no issues. The highest we've been able to properly tune any iron headed units is around the 9.8:1/10:1, no higher, at least not with the proper components. The heads average 260 CFM intake @ .600" lift and 170 CFM exhaust @ .600" also. These are 2.020's and 1.600's for valves. You don't want very large valves in small cubic inch units. You end up with flow issues on the 4.000" bores with any 2.050" valve or larger intended for street use, especially on "non-splayed" heads.

We have some customers that have tried to install larger cams intending
to offset the detonation issues (lowering the dynamic C.R.), but all they accomplish is lower HP numbers/wrong power band, due to wrong combo. Aluminum heads need very different cam specs than their cast iron counterparts.

Most of these combos make power under the 6000 RPM band, and are very "easy" on internal components. We have one unit built in 1999 just back for a "freshen-up" and sent it back with only a ring/bearing change. Springs, lifters, timing chain, etc. were all reused! Thanks, Gary in N.Y.

P.S. To date we have used none of these "off-shore" heads on any 350" SB's. Very few of my own guys want small units anymore! If I had to make a guess on a 350, I would think you could make 400 HP comfortably on pump.

 

Do not think that is correct, if alum and iron heads have the same comb chamber volume they will have the same comp ratio, you can go higher in comp with alum is because of the increased heat dissipation that alum provides.

 

how, exactly, does head material affect the dynamic compression ratio?

 

I was considering going with the Crane 272 Powermax (216/228; 454/480) for a 383 with either some affordable aluminum heads or a good iron head like the Dart Platinum Iron Eagle or the World Products Sportsman II.

I assume that the Pro-Comp would work for this set up. Have you seen this head used for this type of set up?

 

Hi Fevre, if you read the post closer I'm saying exactly what you're saying. There are 2 C.R.'s in the unit, you have a "static" along with a
"dynamic". The "static" is a fixed number with zero variations. Once the unit is assembled that number cannot be changed unless a component is replaced, a piston, a head, a gasket, etc. The "dynamic" however is totally dependent on a whole bunch of other variables. The carb size, the intake choice, the cam specs, the header size, etc., it just goes on and on with the dynamic numbers and those numbers are constantly changing as the unit in being run.

The aluminum heads "pull" heat, from the charge, away from the piston, where the iron heads "reflect" that same heat back towards the piston, there by exerting more downward force. If you build a unit with a 14:1
"static" C.R. and install the cam with a negative lash, in other words, you keep the valves open all the time, you will still have a 14:1 "static" unit, but you will have "0" "dynamic" C.R. one!

I put the example in that context to show that the 2 are not remotely related. This is same theory behind building a low-compression unit, say a 8.5:1 for instance, and staying "small" on the cam to make the unit
"think" it has a higher C.R. It will still have 8.5 but will feel more comfortable driving. Now one other "major" variable is the size, cubic inch, of the individual unit. Larger inch ones tend to "bury" a larger cam. Here again, if you put a 220 @ .050" duration cam in a 265" SB, you will have a "race" cam, if you put that same cam in a 383" S.B. you will have a "gas-mileage" cam. Same cam, different "dynamics".
Thanks, Gary in N.Y.

P.S. The "dynamic" numbers are very important to us when "laying" out a program for a customer. We need to establish how the car will be used most of the time. If this isn't factored in up front, the customer will usually not enjoy driving his particular build. We have a SB over here producing over 730 HP on 93, N.A., and driven daily because the components are a "perfect" match for this customer's purpose.

 

I bought a pair of these heads and the machining looks good. They came assembled from a speed shop in TN and maybe they did some clean up work. I'm in the process of cleaning up the block and getting it ready for the the cam and head install. I'll post more after I complete the work.

 

Are you using the Pro-Comp or the Superflow heads? Also, what machine shop did you use?

 

Did you see under the valves? TERRIBLE!!!!

 

Mine are going to the shop today.

 

Dynamic compression ratio is also fixed when motor is assembled and cannot be changed. It is that compression ratio you get after the intake valve closes ABDC as compared to static compression which uses BDC and the starting point.

You are getting confused with cylinder pressure which changes continuously and intake design, headers, carb etc. factor in

 

 

So, when building an engine, are you more concerned with the Static Compression Ratio or the Dynamic Compression Ration. For instance, if you are using iron heads with 10.2:1, are you OK if your DCR is low enough, or do you still need to lower the SCR?

 

I just bought a pair of bare aluminum Procomp Heads, 190 cc Intakes and 64 cc fast burn combustion chambers. My original '72 487x need new valve guides, springs etc. Cheaper to buy new heads and mothball the old heads. Will post pics soon....

 

How was the machining on those? Would you buy them again if you had the choice or would you go with something else?

Also, do you have any flow numbers for those?

Thanks.

 

Just came by UPS Friday, opened today, they look good to me compared the old GM castings. I have never bought new alumium heads though.
I want to post pics of the chamber, runners and the area under the valves and share with forum members. Will take the pics and try to have posted by Sunday evening.

Here is the link
http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWN%3AIT

 

That would be great. Those are some of the ones that I was looking at. I would be really interested in how good the machining is right out of the box. Thanks.