I'm trying to decide which to go with on my new combo as I have a nice set of 270cc W9s and a set P7s I couldn't pass up. This will be 440" max single stage nitrous plate, leafsprings,28x10.5s. Need to run 5.30s in the eigth at 3200# W9 or 3300# P7. With the new XR block coming I guess I'm gonna go all the way, instead of putting the W9s on my X block.
Looking for some opinions, haven't heard of any 4" stroke P7 combos, or any killer W9 combos. Anyone?

Well thats a hard decision. If you already have the W9's I'd use them. But then again by Februrary or March you caould have a XR block and you can buy complete P7 heads now for much less than W9's.

Hard choice. I guess it all depends on how much money you want to spend

Yea, it looks like the P7 would make a little more power.

I'd like to have put this simple 440W9 Bracket combo on a DTS dyno.... Should make about 870 based on what I've seen (10% more) If it had more cam in it (was 274 @ .050) probably had bit left in it as well. So with different cam, carb & little more tune time, I bet it would tickle 900 on a typical DTS.

I think same motor with good set of Cup P7's on it "should" be 60-70 better. I think a 476ish inch type P7 with between 14-16:1 & big roller will make around 1000 on a "normal" dyno. Biggest thing limiting the P7 for use on big CID & making massive HP is the intake valve size... Yeah they flow alot, & have alot of cross section, but the throat area & valve curtain area is the #1 limiting factor. Most of those heads are 2.20" valve deal....

NE1 have pics of P7 motors, heads and intakes you could post, i'd like to learn more please.

I would not waste my time putting a W9 head on a X block. 59 degree lifters with 1 7/8 lifter spacing. NO WAY NO HOW

But realistically that W9 on a R3 block is going to struggle to make 900 HP unless you run sheetmetal intake and two fours. I make 900 with a cast intake and single four so all of a sudden others think it is easy. It would be if you run two fours and a sheetmetal intake. Cylinder heads are everything. If CFE was so easy to match he would not have gotten all the Pro Stock truck business. I have ran large bore small blocks with big arms and smaller arms the only difference is torque. I like the difference you feel it in the seat on the shift.

I own two sets of P7 heads they flow great numbers but no better than the CFE W8's. I do not plan to gain a thing in HP switching over to the P7's. What I plan to gain is races as if I hurt something I was able to afford spare parts. With the W8 CFE that was not possible and repairs were expensive and pretty much had to be done by CFE if you didn't want some bonehead screwing them up. Tim Davis ran very successful with his W8 heads in PRo Comp. He sat on P7 bare castings that could have been done specifically for drag racing from the start and did not. Not that going with a custom CNC P7 for drag racing is not potentially better than the W8 because it is but the weight break would have made it no worth while. But we are not talking about CFE CNC P7 heads we are talking about old NASCAR takeoffs. They are real nice but no comparison to what could be done from scratch.

If you can afford the wait you should be able to have a P7 XR realistically together sometime mid summer. I have an engine so I can gamble. If the engine sells I have plenty to do while the car sits. So I am rolling the dice on the P7 XR. I plan to build 460-480 CID to start and experiment. After seeing what this stuff is capable of I plan to stretch out and probably have built some Drag Race P7 heads and see how big I can make a small block. With a sheetmetal and two fours 1,000 should be no problem. Limit it to a single four cast intake maybe 930 in a perfect combo.

Like parts of the anotomy every one has an opinion.
Leon

I've picked an entire P7 top end (machined heads w/ titanium valves, ported manifold, TD rockers and stands, valve covers etc..) in anticipation of the XR block, and I grabbed a pair of P7 bare castings and intake off EBAY, so I'm glad to hear you say one could start from scratch on the P7 heads and have them done specifically for drag racing.

P7 Stuff is super cheap right now. The bare heads were 180.00 shipped!

Leon, do you know your 10 degree CFE W8's compare to CFE's 15 degree inline Small Chevy Heads?

No, Steff and the W8's I have are 13 degree not 10 degree. I know you did not imply this but they are not Pro Stock truck heads but are expremely similar. I have not talked to Carl lately but my understanding was the W8's I have are better. Carl has said they were the best inline valve stuff available.

There is nothing wrong with the CNC'ed P7 NASCAR stuff I have two sets. But if I were going all out I would have bare casting sitting in CFE's shop. When you start talking about making 900+ with anything you need to be realistic about the limitations. Personally I am not going to be worried about HP on nuts with the P7 I intend to spray my way to the finish line very quickly. And when I tear it up the dimestore prices of the used Nascar P7's is going to be great.

Huray MOPAR on a budget.

Leon

The only reason I ask is a buddy of mine, using the 15 degree Chevy CFE's on a 427" motor with a BES modified W789 intake & dominator made about 975hp. The motor went 8.49 @3000lbs. I'm kinda' suprised that 900 would be the cap for a w8 or 9 motor with a single 4, if the heads are equally as good. Apperently Bishoff really knows how to make that intake work & yes this motor was set on kill......valve spring eater, high maintainence etc...

Steff,
I know what you are talking about when it comes to HP.I know which motor you are talking about and Davis built a 418 inch chevy that makes the same power with the same intake and he said my heads flow alittle better than his,but the power output of the chevy versus mopar is way off.The chevy still makes more power.Tim still to this day scrathes his head over this and cant come up with a good conclusion....

Tony told me he could easily get another 50 HP out of my intake. We then removed the intake to get the engine in the truck without the trailer hitting it. We found that two of the dividers on the intake the gasket has slipped into the runner. I could not begin to guess how much this lost. Tony said that Tims sheetmetal engine makes big power and would not say how much. But, he did say if he did some intake work and a new set of gaskets I could be real close. I just could not see doing it when the car was so far off to begin with.

LEON

Leon,
50hp is very hard to believe.My engine has the good intake that Tony is speaking of,and tim told me it is more like 15hp.So I dont believe your intake is that bad...50 hp would be worth the money this thing cost.

Fastfish you got any pics of your car?

My 420 intake is basically out of the box. It runs the same as the ported 772 and the 598. Everyone says the 420 is miles ahead well it would be if ported according to Tony. Funny Tim claimed if I bought an intake from him it would be worth a 100 HP when he wanted $2,500 for one of his when this thing got started. I would not beleive anything that came out of Tim Davis's mouth without checking it out for myself.

Leon

Leon,
Tim has always been straight up honest with me on hp ratings,Him and Tony are joined at the hip anyway.2500.00 is alittle steep,so is 100hp though....

Does the P7 NASCAR stuff suffer from some of the problems that the chevy SB2 and SB2.2 heads do? Some of the heads were done for short tracks, restrictor plates etc. and just flat out dont work good for dragracing. I think you really have to do your homework when you buy these cheap heads floating around on the internet.

I have heard of several instances where guys couldnt get them to work and they needed alot of RPM. Some even gave up and went back to conventional stuff....