P-51 stroker

I am looking for some stroker advice. I currently have a P-51 headed 466 (stock block, crank, and rods) and am looking to step it up a notch. What stroker combo takes best advantage of out of the box P-51s, (FMS intake, 1050 Holley, NA)? Strip only. I know that I will need to change the cam and headers, but want to use as much current engine accessories as possible. At what point is a new block necessary (A-460 or Eliminator)? I also have some Milodon main caps (still in box) that I could use on a stock block, but don't want to spend the machining money only to find out I should have just bought an A460 block and be done with it.

Does anyone have any advice on the best way to proceed?

i'm running a stock 2bolt d0ve block.it's never been on a dyno but it runs 5.30's in good air on alky in a chassis car.a stock block can stand a lot of hp as long as the tune is good,750 950 i'd say.a new block is a good investment too.

It seems a lot of guys like the 4.3 stroke with that head, I have no personal experience though.

A set of P-51's out of the box and engine optimized to use all the hp they are capable of is on the boarder line of needing a after market block.

Been involved in three flat top 557's that made 900-905 hp on gas @ 6900 rpm and 780 tq. heads out of the box with ported Victor intakes.

I would like to know more about those 557 combinations. My intent is to stay with a combination that will still work with 110 octane gas and not be so much on the ragged edge that it needs "extra special" attention to last. I'm not looking for the exotic setups, but want as much as I can get without stepping up past the current head I have.

I currently have good ignition, a good fuel system. a glide with a 9" ultimate converter concepts convertor, and a Strange 9" w/ 31 spline axles. I am fully aware that the entire package needs to blend together and that it is only as strong as its weakest link. I just want to make sure my engine isn't that link.

Given an option of adding 4 bolt caps to a stock block or buying an A460 block, which is the most cost effective solution?

That head will flow enough air to more than satisfy your 466 at a high enough RPM however, the steel valves and springs which come on those heads aren't appropriate for much over 7,200 RPM.
A 501 at 7,100 RPM, (4.150" stroke) or a 521 at 6,500 RPM, (4.30" stroke) will take best advantage of those heads "out of the box", (which does include not changing the hardware on them), as long as the engine is cammed appropriately.

Ok... my "out of the box" meant that they had not been cut on - no shaving, no porting (intake included) I put Ferrea 6000 series valves (2.25 and 1.76) and Comp's recommended springs to go with their cam. I make the assumption that springs would have to be changed if the cam was. Right now, my cam is comparitively small (Comp XR-280R-10, .657/.664 and .242 / .248 @ .050). Springs are Comp #954. They have the Jomar girdles on top and Howards Cams roller rockers with Trick Flow 3/8 push rods. I am also running the Comp roller lifters.

I cannot spin my 466 fast enough to accomodate the heads as I have stock rods.

The Ferrea 6000 series valves are where I'd have a concern. That is not their premium valve. Furthermore most likely they are .100" too short. The correct Kaase P-51 valves intended for those heads are 2.250" X 5.365" long and a tuliped exhaust valve that is 1.760" X 5.160" long and flows better than the Ferrea valve . With the Kaase valves you can have a 2.000" installed height and therefore a better valve spring selection for the bigger roller cams.

Your new Milodon 4 bolt main caps work best on a 1970 DOVE-A block and I would not fool with trying to put them on the other stock blocks. Just go ahead and buy the A-460 racing block if you do not have a DOVE-A.

Hope this helps,
Charlie

Ok,,,, It seems as though every time I start a project it quickly becomes pretty deep. This is all good stuff to know... I believe my valves were shorter than the Kasse valves. I don't mind changing vavles if it is needed. Is there a preferred brand/style of valve to have for these heads? How much gain can be had with porting the heads and/or intake?

Every response creates more questions for me. Thank you all for your expertise and patience.

My wish list:
- a dependable "torque monster" type engine that can perform on the dragstrip without stressing its rpm limit,
- one that can use my existing heads, intake and carb, moroso oil pan, FMS balancer, (my current headers are only 2" primaries)
- naturally aspirated on 110 race gas (maximum)
- I would like to push my 3100 lb fox body toward the 8's
- I want good quality materials that I can worry less about breaking (i.e. forged crank, good rods and pistons)

How easily is this achievable? What kind of hp can I get out of a 521? a 545? or a 557 in this scenario? Does a .030 bore add reliability over a wider bore? Is there an advantage of the 4.3 stroke over the 4.5? Where is the "sweet spot"? I understand there is a lot of science involved. I just know that most of these combos have been tried. Do any of these combos have a good piston that is more affordable than another (i.e. is the 521 piston much less than the 557?)

460Dave wrote:Ok,,,, It seems as though every time I start a project it quickly becomes pretty deep. This is all good stuff to know... I believe my valves were shorter than the Kasse valves. I don't mind changing vavles if it is needed. Is there a preferred brand/style of valve to have for these heads? How much gain can be had with porting the heads and/or intake?

Every response creates more questions for me. Thank you all for your expertise and patience.

My wish list:
- a dependable "torque monster" type engine that can perform on the dragstrip without stressing its rpm limit,
- one that can use my existing heads, intake and carb, moroso oil pan, FMS balancer, (my current headers are only 2" primaries)
- naturally aspirated on 110 race gas (maximum)
- I would like to push my 3100 lb fox body toward the 8's
- I want good quality materials that I can worry less about breaking (i.e. forged crank, good rods and pistons)

How easily is this achievable? What kind of hp can I get out of a 521? a 545? or a 557 in this scenario? Does a .030 bore add reliability over a wider bore? Is there an advantage of the 4.3 stroke over the 4.5? Where is the "sweet spot"? I understand there is a lot of science involved. I just know that most of these combos have been tried. Do any of these combos have a good piston that is more affordable than another (i.e. is the 521 piston much less than the 557?)

I understand what you are doing and the heads now match the camshaft you have.
That said. this combination will get nowhere in the 8's without nitrous.

With a 521 stroker engine and the components you already have would probably get to around 700 horsepower with good tuning and IF the 3,100 pound car and the rest of the drive train are really RIGHT, should approach the mid nines.

Somebody has misinformed you about what it actually takes to go that fast; especially how much it will cost.

the parts needed to meet your goal with an n/a combo are not gonna be streetable..........

There are several on here that have accomplished what your asking with that said. They all have compression that exceeds 110, and there is a ton of work in accomplishing it. As Randy has mentioned doing it NA at that level and weight would be next to impossible. Build it for a bottle and things become simplified drastically.

You can go low 9,s or better with your heads and flat tops on a 528 or 534 , but it will take 112 fuel as you will be close to 14:1 compression.

And it will be far from streetable, or at least by my definition. It will have to be camed correctly and tuned correctly to do it.

I was thinking back about Damons engine, he runs low 9,s at a heavier weight than the OP.

I am not trying to be streetable and I'm not married to my wish list. It was a starting point to throw out. Maybe I should have stated that I wanted to be in the mid to low 9's. I don't really see 8's in my foreseeable future. I just want to be headed that direction. I have seen plenty of guys do it w/ nitrous, but don't know that I want to go there yet. What size was Damon's engine?

Randy, your comment about the mid 9's with a 521 makes perfect sense. Will the 521 limit me from going any further, or is mid 9's about as much as I will ever see out of that combo? I have a feeling that I will forever be searching for another .10th. What stroker combo will allow me some growth, or to take advantage of a nitrous kit later? It is understood that increasing power in one area (engine) requires changes in other areas (tranny, rear, etc.), but you have to start somewhere. I would rather have more engine than car over more car than engine at this point. It feels like I am opposite right now.

I see the comment about building it for a bottle and things becoming simplifiied. I may sound stupid for asking this question, but I have never had a nitrous engine... so here goes. Can I build a strong NA engine and then just add a 250-500 plate system to it later? Can a valvetrain combo compromise between the two enough to be effective? or would adding nitrous require a cam change? Can I cam it for nitrous and still be effective running NA? OK, it sounds stupid as I am typing it. I know that a full effort engine requres dedicated parts (i.e. nitrous cam for nitrous engine, NA cam for NA engine). The more performance focused an engine, the less room for compromise. Am I past the point to compromise in that area?

You can build a engine that runs good NA and on spray at those nitrous levels, your converter will be more of a compromise than anything.

460Dave wrote:I am not trying to be streetable and I'm not married to my wish list.

Randy, your comment about the mid 9's with a 521 makes perfect sense. Will the 521 limit me from going any further, or is mid 9's about as much as I will ever see out of that combo? I have a feeling that I will forever be searching for another .10th. What stroker combo will allow me some growth, or to take advantage of a nitrous kit later? It is understood that increasing power in one area (engine) requires changes in other areas (tranny, rear, etc.), but you have to start somewhere. I would rather have more engine than car over more car than engine at this point. It feels like I am opposite right now.

Your cam is about 30 degrees to small on the intake side and about 35 to small on the exhaust side. AND, that is just a start.
First, you are going to be limited to around 850 horsepower unless you get that power with RPM and not torque and also stay completely free of ANY detonation. A 521 is a good compromise for a high horsepower, STOCK block combination.

Here is Damon's build. This could be done in a stock block with 4 bolt caps. But pushing the limits, I ran a TFS Street headed engine for several yeas and several dyno sesions, @ 860 hp on a stock block and after market caps with no problem.

https://www.429-460.com/t282-534-ci-a429-heads-roller-drag-car-combo

Just swap on your P-51's and make more power.

One of my good buddies Melvyn (514fox87) on here has been 9.30 at 145 mph still spinning off the line (1.40 plus 60' times) in his fox that weighs 3010 on 10 inch slicks with a 466 inch with ported aluminum cobra jets and custom solid roller with diamond 14 to 1 pistons ,and expected to be faster now that he got his converter back in from ucc last week, not bad for a small inch motor and we wonder what it would run in my fox cause its 2650 lbs with driver ?

FWIW, I'm expecting my P headed 514 to run low 9's in my Fox.

Where did you get your heads? Kaase or Lem?

I have run 9.40s @ 3400 lbs on motor with a nitrous converter and a power glide with unported P51s. I do have an aftermarket block however and 572 CID.

If I were to buy P51s today I would have got them bare as I replaced the valve springs with some much stronger ones and went with titanium retainers.

Charlie is now porting them and putting in 2.300 titanium intake valves. Hopefully it will pick up some.

That's why I asked where he got them from. I got mine from Lem with titanium retainers and nice springs.


Didn't take you long to tear it down to go faster did it????

a year and 2 months. once i get the heads back it will only be an afternoon to put it together.

Heads are coming soon

Charlie

psfracer wrote:I have run 9.40s @ 3400 lbs on motor with a nitrous converter and a power glide with unported P51s. I do have an aftermarket block however and 572 CID.

If I were to buy P51s today I would have got them bare as I replaced the valve springs with some much stronger ones and went with titanium retainers.

Charlie is now porting them and putting in 2.300 titanium intake valves. Hopefully it will pick up some.

....awesome cant wait to see the results

To the OP, I'm running a 13:1 552ci/C6 P-51 headed combo in a 3000# '69 Mach 1 small tire car to consistent 10.40's na with 8000ft DA at the mile high track at Albuquerque, NM. Foot braking it. Consistently. Gas not alky. It's not setting the strip on fire like some of the hero's on here but its a home built street car with legit tags on it for cruising to Sonic. Correct for the retarded DA and it should legitimately run about .7 quicker at a sea level track in good air. And it's not certed for 9.99's... nor am I.

As I said, I don't have a glide, no trans brake (yet), all tuning, lash, suspension setup by me, no phfatt slicks, no scaling, no head work, 2" primaries, std Holley brand 1250... in other words there are certainly gains to be had by somebody who's a real old school jedi or wants to keep pushing it. With a good combo under those heads and a setup/efficient car I think mid to low 9's na is certainly doable at 3100#. FWIW. Good luck.