p51 heads vs scj heads??? for money what one is the best

p51 heads vs scj heads??? for money what one is the best

i ve narrowed down to these to sets of heads , trying to figuare which ones to

get was gonna get some scj but then ive heard the p51s are realy nice for money ?

I posted this same question a month or so ago and after much debating I called Lem and discussed my goals with him and would recommend you do the same he is very informative and knowledgable about these heads. Also you should fully decide what your plans are now and in the future.
Here is a link to that topic: https://www.429-460.com/engine-tech-f2/scj-s-or-p-51-s-t2473.htm

at the current price a set of SCJ's is hard to beat if you going to use them out of the box. definetly a big improvement over stock stuff.

The P-51 are a great upgade over the scj's also......... comes down to $$$$ IMO

Food for thought:

- What are your long term plans for this engine?

- Will the SCJ's (ported/max effort) accomplish the long term plans?

- Will the P-51's satisfy your long term plans in an "Out Of The Box" set-up or will it take addisional work (porting/max effort) for them to satisfy your long term plans?

So is spending more $$$ for the P-51s a better buy (in the long run) or will the SCJ's do all that you want for less $$$???

Like I said, food for thought and as dfree383 has already mentioned "at the current price a set of SCJ's is hard to beat if you going to use them out of the box. definetly a big improvement over stock stuff."

its all about application ....... its best to discuss your goals w/ your engine builder ..... there is no best like Randy said

My neighbor builds engines, and had a few people switch from ported SCJ's to P51s when they came out. Most had zero improvement in et. This anecdotal evidence proves nothing, because there are too many variables involved, and who knows what kind of cork in the system or tuning screwup was causing the results. So there ya go. I am always happy to say nothing in my attempt to help.

cletus66 wrote:My neighbor builds engines, and had a few people switch from ported SCJ's to P51s when they came out. Most had zero improvement in et. This anecdotal evidence proves nothing, because there are too many variables involved, and who knows what kind of cork in the system or tuning screwup was causing the results. So there ya go. I am always happy to say nothing in my attempt to help.

Ported P-51's vs ported SCJ's of Ported SCJ's vs unported P-51's? Please clarify?

dfree383 wrote:

cletus66 wrote:My neighbor builds engines, and had a few people switch from ported SCJ's to P51s when they came out. Most had zero improvement in et. This anecdotal evidence proves nothing, because there are too many variables involved, and who knows what kind of cork in the system or tuning screwup was causing the results. So there ya go. I am always happy to say nothing in my attempt to help.

Ported P-51's vs ported SCJ's or Ported SCJ's vs unported P-51's? Please clarify?

I had the same question. It was most likely Non-Ported P-51 vs Ported SCJ (may have been Max Efforted Ported SCJ).

dfree383 wrote:

cletus66 wrote:My neighbor builds engines, and had a few people switch from ported SCJ's to P51s when they came out. Most had zero improvement in et. This anecdotal evidence proves nothing, because there are too many variables involved, and who knows what kind of cork in the system or tuning screwup was causing the results. So there ya go. I am always happy to say nothing in my attempt to help.

Ported P-51's vs ported SCJ's of Ported SCJ's vs unported P-51's? Please clarify?

Several different scenarios. Too many variables to keep up with. Which is why I made sure to say, " This anecdotal evidence proves nothing." I was just relaying his general impression of both heads (many sets) in local guys cars with local guys tuning them and running them. Can you see how it would be very "non scientific" ?


Even Mr. Kaase mentioned that every few years they will play with the ports, test with the flow bench, and get no et improvement.

From what I have read and seen a P51 out of the box is what a max ported SCJ head is. The pistons are the same for both heads also. We are working on a 4 cylinder engine that uses a 460 type head and we chose the SCJ because of the cubic inches (243) and the camshaft limitations. The "best" head will not always perform the best because of different combinations. We felt the P51 was too big four our combo. There are a lot of factors to consider.

All depends on the combo. For a street car the SCJs are probably the better option. Smaller ports to work with initially, bette rvelocity, etc...

For an all out drag car like mine the P51s were the better choice. I don't have the money to spend on changing a combo every year or two. I figured I'll spend a little more now on some P51s and run them for a few years. When I'm ready to upgrade the cubes from the 514 to say a 572, etc... it'll take minimal effort on the head side to do that.

That and I liked the out of the box numbers I can get with a set of the P51s. More bang for the buck in an all out race application IMO.

ive posted it several time gonna do a 545 hoppin 13.1 ish and hoppin to get car 9.00-9.50 in my mustang
this is gonna be a track only car with a glide

if your building a totaly new engine and don't have anything your reusing, A460 heads are a better bang for the $$$ IMO and have alot more potential in then than the conventional heads do.

whats the deal on the a460 heads valve shrouding ect....on my d1ve block with a .030 bore with a460 heads what head gasket would i use....considering its only a 4.390 not a real big bore

for what im gonna do i think scjs or p51 would be fine but maybe im wrong, havnt got a cam yet either .....gotta call lem on that

Even with the shrouding the a heads have more potential and will go down the track faster IMO

dfree383 wrote:if your building a totaly new engine and don't have anything your reusing, A460 heads are a better bang for the $$$ IMO and have alot more potential in then than the conventional heads do.

Not to mention for those budget minded these pop up used all the time for a good price and would easily meet your goals.

One's goals and budget dictate everything . One can spend a little to get lot or spend a lot to get very little . It's a matter of planing i.m.o.

5pointslow wrote:ive posted it several time gonna do a 545 hoppin 13.1 ish and hoppin to get car 9.00-9.50 in my mustang
this is gonna be a track only car with a glide

I would definitely go with the A460 heads on a 545. It should make around 900-950 HP.