[Hooter]

Old motor in my street car 65 was a 4.75 stroke 565 pump gas motor. Made 820 hp at 6400 before and can't recall the torque(quite a bit). Now, destroked with a Molnar 4.375 crank, same length 6.7 rods(pin is now out of the oil ring) and Diamond pistons. Compression will remain the same at 11.5(had to use a thicker head gaskets with the previous increased stroke so better quench now). Old motor had low tension rings and a vacuum pump. New motor has standard style rings an no vacuum pump. Here's a few quick particulars:

KRE block at 4.35 bore
CV1 out of box heads and low rise intake
1050 BLP dominator
Comp 4/7 swap cam. 276/284 on a 113. 700/726 lift after lash
Comp roller rockers with stud girdle
Same POS Heddman 2" headers with flat 3.5" collector

Essentially it's the exact same motor minus the stroke and low tension rings/vac pump. Destroked due to blowing a roller lifter on Drag Week 2 years ago and putting trash all through the motor. Pistons pretty scuffed up and decided to make the motor more street friendly.

Going on the dyno tomorrow. Curious what you guys think it will make compared to before..

[johnta1]

Probably need higher RPM peak.

775 HP

[Half-Inch Stud]

Curious what fuek was/will be used, and the difference in timing. Think HP will be same but at diff RPM or 1% lower (due to rings).

[firechickenman]

I think it will lose some HP but not much and will make it at higher RPM. It will lose more torque. Good luck!

[mgarblik]

Originally Posted by firechickenman

I think it will lose some HP but not much and will make it at higher RPM. It will lose more torque. Good luck!

I think you will give up about 30-35 lbs. torque and have a slightly narrower torque curve. If you can make HP at 800-1000 RPM higher, peak HP will be near the same. Have fun on the dyno.

[Hooter]

Fuel will be 93 octane pump gas. Same as before. Kinda figure will spin it to 7,000 or so this go around depending on what it likes. Previous timing was at 28 degrees.

[steve25]

X2 with reply number 5.

[PAUL K]

Idk....but good luck!

[slowbird]

Same dyno facility correct?

[John Langer]

When I went from 525 to 565 I picked up only around 45hp peak but like 70 average in the power band and gobs of torque. Going in reverse expect similar results. On my change I just changed rods and crank. Everything else was identical.

[Hooter]

Originally Posted by slowbird

Same dyno facility correct?

Yup

[slowbird]

Originally Posted by John Langer

When I went from 525 to 565 I picked up only around 45hp peak but like 70 average in the power band and gobs of torque. Going in reverse expect similar results. On my change I just changed rods and crank. Everything else was identical.

Im curious if your peak rpm changed much?

[Dave M]

Good luck Hooter!!


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[jonmachota78]

Similar HP more rpm. Good luck!

[mgarblik]

Originally Posted by John Langer

When I went from 525 to 565 I picked up only around 45hp peak but like 70 average in the power band and gobs of torque. Going in reverse expect similar results. On my change I just changed rods and crank. Everything else was identical.

That's a good data point.

[Probird]

I'm going to say it will lose about 50hp. A few from less ci and 25 or so from losing the low tension rings and vacuum pump. So my guess is 770hp.

[Hooter]

I'll be happy if it hits 775. The car is getting a cage so I can legally go 9's this year. Hoping I'll have enough motor to do that with the downsizing lol.

[BADDTA]

Originally Posted by Hooter

Old motor in my street car 65 was a 4.75 stroke 565 pump gas motor. Made 820 hp at 6400 before and can't recall the torque(quite a bit). Now, destroked with a Molnar 4.375 crank, same length 6.7 rods(pin is now out of the oil ring) and Diamond pistons. Compression will remain the same at 11.5(had to use a thicker head gaskets with the previous increased stroke so better quench now). Old motor had low tension rings and a vacuum pump. New motor has standard style rings an no vacuum pump. Here's a few quick particulars:

KRE block at 4.35 bore
CV1 out of box heads and low rise intake
1050 BLP dominator
Comp 4/7 swap cam. 276/284 on a 113. 700/726 lift after lash
Comp roller rockers with stud girdle
Same POS Heddman 2" headers with flat 3.5" collector

Essentially it's the exact same motor minus the stroke and low tension rings/vac pump. Destroked due to blowing a roller lifter on Drag Week 2 years ago and putting trash all through the motor. Pistons pretty scuffed up and decided to make the motor more street friendly.

Going on the dyno tomorrow. Curious what you guys think it will make compared to before..

Not enough to keep up with the little stock block.

Brian

[Hooter]

Originally Posted by BADDTA

Not enough to keep up with the little stock block.

Brian

My first call out... that is a bad little stock block sob. Guess I shouldn't of sold you guys the block lol

[John Langer]

Originally Posted by slowbird

Im curious if your peak rpm changed much?

Exact same rpm. Now going from 477 to 525 was a around 6-800 difference in peak rpm