Guess my horsepower

[mike7570]

620

[machoneman]

Hah! Didn't see your guess. I'll make mine....

579.5

LOL

Me and you are gonna be wrestling around Machoneman.

[Jim Comet]

A little background, I started with just wanting Blairs Pro Port heads for my 390. I was then going to use the same cam as he used in his dueling 390's (which made 579hp) on my freshend short block. After taking my short block apart I started second guessing the block integrity and factory rods at that power level. I then talked to Blair and decided to go with a new block and the internals from post #1. I figured with him doing the assembly, 20 more cubic inches, a bigger solid roller cam and 850cfm carb I should be good for 600hp. No matter where the power numbers end up, I am sure it will be faster than my old home built 390 that ran low 12's.  More importantly it will be much more bullet proof. I didn't go the 445 route because of the limited tire room on my 66 Comet. Hopefully I can and will be consistent as this is a footbrake bracket car. Jim

[70tp]

570

[Nightmist66]

Can't wait to see the results. Looking at the header flange, you went with the race pro port? Are the heads angle milled? Are the collectors from REF? Did the block get cross bolted? My heads also have 54cc chambers. I went with street pro ports. Other than a couple more cubes, the build is very close to mine.

[Jim Comet]

This may sound uninformed but I believe they aret the steet Pro Port. They are however his latest design which changed in the last couple of years. The collectors are Ebay Items which I may decide to change in the future depending on results. The block is not cross bolted but the #2 and #4 mains are drilled deeper and I am using the older ARP studs whick have about 1/4 inch more thead into the block. Blair thinks that with the smaller jounal, ATI dampner and his other details, this short block should be ok to 7000+ rpm. Jim

[Nightmist66]

If the exhaust port is mostly round and raised, it's the race port, if it's squareish, it's the street for shock tower cars. I decided to cross bolt mine for extra insurance. Custom 4140 steel cnc'd caps press fit to block. I may do a thread at some point if anybody still cares about 390's. Okay, I'll shut up about my junk now. Good luck with yours.

[Jim Comet]

One other thing about block strength. I had an older set of ARP main studs (1996ish) and the threaded portion that goes into the block has about a 1/4 inch more threads than what the newer ones now being sold by ARP have. Blair liked that they have more thread engagement for strength.

[machoneman]

Nice but methinks maybe not so much help.

Keep in mind that Ford's engineers added cross-bolts to what was essentially the identical block architecture (390 through 427) over the years for a reason. That and as the cross-bolt size is substantially smaller than main bolt size, they must have thought that was still strong enough to tighten the lower end and prevent block cracking. The BBM website explains this well, even though their blocks seem to be near unobtainable. http://www.mustangandfords.com/how-to/engine/1408-reproduction-fe-series-427-crossbolt-blockbuster/

One other thing about block strength. I had an older set of ARP main studs (1996ish) and the threaded portion that goes into the block has about a 1/4 inch more threads than what the newer ones now being sold by ARP have. Blair liked that they have more thread engagement for strength.

[CaptCobrajet]

Well, we made 687 power at 6500 and 630 torque at 4800 yesterday at Bischoff's with a 12:1, 504 cuber.  It has heads like Jared's.  Jim, Jared, and the one we ran yesterday all have the same "street" intake port.  Stock Medium riser port location, with the roof slightly raised at the flange.  Jim has the "race" exhaust port, where these others are a stock exit location.  I changed ratios on the rockers, because the lift at the valve was not checking to spec.  The baby roller is only .525 lift, so only .515 after lash.  T&D rockers are the only ones that will check correct with the cam card. All others need more ratio to get there.  Having only .500-ish lift, I don't want to give up anything to "light checking" rockers.  Both Jim's, and the one I just ran have rockers that correct the problem.  I got a little more on Jim's so it has about .530 after lash on the intake.

Those heads flow almost 320 at .500 on the intake, and about 230 on the exhaust at .500.  It will peak closer to 7000 with the 3.98 crank.  Yesterday's unit had a 4.250 crank and more inches, so peak happened sooner.  This bigger engine had 20-25 hp left on the table in terms of a peak number, but it is a street engine, and the carb spacer I used will make it a little more responsive in the middle.  Horsepower per cube will go up when using a better head, more compression, and less stroke.....have fun speculating, fellers.  I like this HP guess game.

It will be interesting to see the results on Jim's piece.  A little more compression, and a better exhaust port, higher peak point, but less inches.  I don't like popcorn, so I'm gonna sit back and eat peanuts and spectate!

[fryedaddy]

yes this is a fun game.i hope its here to stay.love guessing on the different combos.i will admit i changed my rpm after reading Blair's reply.

[TomP]

12.8 compression! I guess if you have the octane available, why not.
 Kind of odd having that low lift, is there any reason for that not being well over .600?

This sounds like a real stout piece and i'm sure it ought to go better than 12's in a LTD stretch limo.
 I will say 616hp... like a Cammer made.

[CaptCobrajet]

Yes Mr. Tom.  I created the "baby roller" for several reasons.  First, the lower lift does not screw up the geometry on the OE style rockers.  Second, it doesn't require going to the paired shaft T&D, but you can still get all of the benefits of a solid roller without pulling the studs out of the heads.  If the heads are good, it'll make power at .525 lift.  The SPP still flows more at .600-.700, and there is more power there.  We've seen 800 hp with the stock location exhaust with .700 lift and compression, and 925 hp with the SPP with raised exhaust, compression, .800 lift, and a dry sump..... but you could drive this baby roller coast to coast, race it for 24 hours, or drag race it for YEARS, without durability issues in the guides, springs, or valvetrain.  Plus, it won't wear a lobe off after it sits all winter!  It is intended for better than average performance, and better than average reliability.

[fryedaddy]

Yes Mr. Tom.  I created the "baby roller" for several reasons.  First, the lower lift does not screw up the geometry on the OE style rockers.  Second, it doesn't require going to the paired shaft T&D, but you can still get all of the benefits of a solid roller without pulling the studs out of the heads.  If the heads are good, it'll make power at .525 lift.  The SPP still flows more at .600-.700, and there is more power there.  We've seen 800 hp with the stock location exhaust with .700 lift and compression, and 925 hp with the SPP with raised exhaust, compression, .800 lift, and a dry sump..... but you could drive this baby roller coast to coast, race it for 24 hours, or drag race it for YEARS, without durability issues in the guides, springs, or valvetrain.  Plus, it won't wear a lobe off after it sits all winter!  It is intended for better than average performance, and better than average reliability.

does this baby roller work good in your cobra-jets and how much hp and rpm can you get out of this cam in a 428

[CaptCobrajet]

All depends on what the goals are, and what the combo is.  "Cobra Jets" is a pretty broad term.  Lots of ways to cook 'em.