[Steve C.]

ta man's post about a high strung 400 brings up tall tales............

Pete McCarthy wrote a article in the July/August 1997 issue of Pontiac Enthusiast magazine with the title, "Building a reliable 660-hp Pontiac 400 bracket engine".
Crankshaft Specialties of Memphis, Tenn., prepared a hard chromed 400 crank machined for Chevy-journal 6.8" aluminum rods with tapered .980 pins. The rod journal offset was used to increase the stroke from 3.75" to 3.79". With a bore size of 4.181", total 416 CID. t was a '73 400 block, filled to within an inch of the deck. No street duty. A canton kick-out oil pan with a "shorty" windage tray. Longer dowel pins and main-cap studs were used with the steel 4-bolt main caps. heat treated 80-lb oil pump. The cam selected was a UltraDyne 310/314 R6 solid roller, which featured 279 intake at .050" and 283 at .050 of exhaust duration on a 106 LSA. Duration at 0.200" was a fat 204 degrees intake and 204 exhaust. The lifter bores were braced. The heads were heavily ported RAIV iron heads done by Pete. Ross flat-top forged pistons were used and I believe it was a 11:1 compression. Tom Doss custom headers round port headers. It used a Dominator carb, I suspect the Victor intake was used if it was in production then. Peak torque on the best pull was a whopping 551 ft.lbs. at 5700 rpm, with a wide curve above 500 ft.lbs. extending from 4000 to 7000 rpm. Peak power occurred at a surprisingly low 6,800 rpm, and hit an almost unbelievable 669.3 hp.

It was the 400 that thinks it's a 455 !


.

[steve25]

And the above was with ported iron RA4 heads!

[Steve C.]

Stan,
A fwiw, your HP cfm flow data doesn't jive with their published data. Did I miss something involving the program.

https://www.tinindianperformance.com...cylinder-head/


.

[Steve C.]

steve25

The article was a bit confusing. Pete mentions his max performance 400 bracket racing engine using ported "670" heads. It had a rod bearing failure.
In preparation with the articles build he had just finished a set of 1969 "722" heads. These were sent to Jim Butler for the build. In the article he said ... "adding up the minuses, I estimated some 20-30 HP would be sacrificed, but that the extra 30 cc's and 30 cfm airflow of the ported RAIV heads over the 670s would break me even." "As it turned out, I grossly underestimated the power of the new combination, even with the concessions."

There was never any mention of the cfm flow for any of the heads.

.

[Stan Weiss]

Originally Posted by Steve C.

Stan,
A fwiw, your HP cfm flow data doesn't jive with their published data. Did I miss something involving the program.

https://www.tinindianperformance.com...cylinder-head/


.

Steve,
The flow maybe off a little. Note those number are at 20" of water (which the program will adjust for) not the more standard 28" of water.

Stan

[slowbird]

Originally Posted by PontiacLars

Thoughts on running KRE high ports 64cc on a .030 over 400?
Cast eagle crank, Icon 4.5cc pistons, eagle h-beam rods
and performer rpm intake.
With a big solid roller, do you think this combo will be far from 600 hp?
Fueling will be Fitech 800 EFI and MSD distributor.

Having a hard time considering another head when this head give 330 flow, titanium retainers, 1200 series valves, PAC springs ++
Allready have round port headers, so D-ports are not an option.

Can you define big solid roller?

[PontiacLars]

Interesting points being made on the high ports negative details. If up to and above 700hp can be made with Edelbrock round ports, and valve train is lighter, why bother?
Only problem now is getting Edelbrock heads..seems that they are not available anywhere.

[PAUL K]

The Hi-ports for your combination have a better than 90% chance of leading to disappointment. FWIW

[PAUL K]

Originally Posted by PontiacLars

Interesting points being made on the high ports negative details. If up to and above 700hp can be made with Edelbrock round ports, and valve train is lighter, why bother?
Only problem now is getting Edelbrock heads..seems that they are not available anywhere.

You can build a nice 400 with factory iron heads. They're readily available. Search out a good head porter instead of the aluminum heads.

[chuckies76ta]

You can build yourself a nice 550 to 600 hp engine with KRE d-ports, Torker2 intake and still have decent vacuum. Sell your round ports and buy yourself d port headers. You'll need a hydra boost braking unit if vacuum is low or manual brakes. We ran my wife's 68 Firebird with pretty much stock into the high 10s with Kre D ports. 3650 weight.

[i82much]

Butler says 8-10 weeks for ported edelbrock 72 cc round ports:

https://butlerperformance.com/i-2445...tegory:1394343

[PontiacLars]

I looked at cylinder heads and found that I can get e-heads, part number 60599 and the Speedmaster cylinder heads. The e-head has the old style chamber, speedmaster has cnc hearth shaped. Roller springs in speedmaster, flat tappet in Edelbrock.
The price are the same for both.

Considering going forged 4.25 stroker. I am scared of the cast 3.75 eagle will destroy my engine…