[slowbird]

Building a new engine for our 69GP. Just curious what people think it'll make.
Its a 11:1 463ci with a 242-247 HR cam .640 lift, kre d-port heads flowing 320+in 230+ex (2.11x1.77 valves), topped off with a RPM intake and 950Holley and1 3/4 headers.

[tom s]

625

[pastry_chef]

Any work to the RPM intake?

[slowbird]

Originally Posted by pastry_chef

Any work to the RPM intake?

Port matched and blended for the square bore carb.

I will add there is nothing special/trick done in the short block

[Scott Stoneburg]

575hp. Would be my guess.

[ta man]

600plus..I like the compression ratio. Any more details on the head/cam combination?

[slowbird]

Originally Posted by ta man

600plus..I like the compression ratio. Any more details on the head/cam combination?

Like?

[ta man]

Originally Posted by slowbird

Like?

Yes..great compression for those heads ..should have no issues with pump gas.

[ponjohn]

605 / 635T

[Tom Vaught]

635 hp
Tom V.

[chuckies76ta]

600 hp 600 t

Charles

[yellow1098]

How much does the compression come into play for the numbers .....I have a 461 with 340 heads and I was hoping for 650hp but I’m only at 10:1

[Formulajones]

I've built combos very similar to that in the past and dyno'd them.

I don't believe it'll hit 600hp, with that cam, heads, and intake on an honest dyno.
None of them I've been involved with ever did unless something like the cam and intake profiles were changed around.

More like 570-580hp, but it will make boat loads of torque, likely over 600 ft lbs.

[slowbird]

Originally Posted by Formulajones

I've built combos very similar to that in the past and dyno'd them.

I don't believe it'll hit 600hp, with that cam, heads, and intake on an honest dyno.
None of them I've been involved with ever did unless something like the cam and intake profiles were changed around.

More like 570-580hp, but it will make boat loads of torque, likely over 600 ft lbs.

That sounds like a challenge, i accept. Lol.

[Formulajones]

Originally Posted by slowbird

That sounds like a challenge, i accept. Lol.

Wasn't knocking the combo, I've actually liked that particular setup for a nice street engine. Just that they don't tend to reach 600hp like that, and that's okay.

I've done 463-467ci with conventional style 320-330 cfm heads, usually round ports but the KRE D-ports you're using are similar. My favorite cam in a few different engines is the 242/248 grind very similar to what you're using, and I almost always use that RPM intake with a 950hp carb. Those engines I've done all used 2" headers though, not smaller 1 3/4 that you have.
The Pontiac just simply peaks around 570-580hp like I mentioned, usually around 5800-6000 rpm but they make boat loads of torque. Very table top flat and just over 600 ft lbs. It's a great street engine and will run mid to low 11's in a 4000 lbs street car out here.
Now if you were to step up the heads to a high port, or some serious porting on the conventional head, and maybe a little more cam, or a good single plane intake to push peak HP and rpm up a bit, I could see it. When using the RPM intake, I had to use a 1" open spacer to get the peak HP up where I predicted for your combo, but it still wasn't 600hp.

The only way I've been able to top 600hp with similar combos like that is with a BBC. 461 ci, 10.2:1 compression, RPM air gap intake and 950HP, again with 2" hooker super comp headers, and the same 242/248 camshaft, but with far superior AFR heads that flow 370 cfm, but they are still a conventional BBC head with nothing fancy. It makes 612hp up at 6300 rpm but it simply doesn't make the torque like a Pontiac, in the 580 range at a higher rpm. It's really the cylinder heads that are doing it. Far better than a conventional Pontiac head, so I don't need as much camshaft to make more HP. Personally I like the torque curve of the Pontiac. Not knocking your combo, it's a great all around package that isn't too rowdy.

Now you may find a dyno that'll move the numbers around a bit, but it is what it is. I'd like to see a video and dyno sheet, as long as they give you BSFC and LBS. per hr numbers.

[i82much]

don’t wanna pee in your wheaties but thought i heard the rpm might have a lean cylinder or two in applications pushing that kind of power. maybe try a T2? or at least do a forum search to see if you find any info on that issue.

[4dblnkldude]

I'll play...I say 622

[slowbird]

Originally Posted by i82much

don’t wanna pee in your wheaties but thought i heard the rpm might have a lean cylinder or two in applications pushing that kind of power. maybe try a T2? or at least do a forum search to see if you find any info on that issue.

Not worried about it. But we will be testing a couple intakes including a tri-power.

I sure hope some of you guy are right but i think there are a lot of optimistic guesses here.

[i82much]

Originally Posted by slowbird

Not worried about it. But we will be testing a couple intakes including a tri-power.

I sure hope some of you guy are right but i think there are a lot of optimistic guesses here.

ok cool. if you decide to post the results i will definitely look forward to seeing them.

[Steve C.]

A related combination for interest....

SD Performance KRE D-port 300-305 cfm CNC ported heads.
10.5:1 compression ratio
Comp part # 51-000-11
Grind # P8 3115B / 3116B HR112.0
.006" - 306 / 314
.050" - 246 / 252
0.4000" lobe lift intake & exhaust / 1.52 rocker ratio
112 LSA
Crower solid roller lifters w/ .005" lash
Minimum 150 lbs seat pressure after run in

.030-over 455 / 4.250" stroke
Torker II intake port matched to the heads w/1-inch open carb spacer
Holley HP950 carb
1.75 headers

588.5 HP at 5800 rpm
600.6 ft.lbs. torque at 4600/4700 rpm


.