Pump gas 421 SBC HP

[mt-engines]

Final graph

[Carnut1]

I love these small cam builds. Mt, any porting work? Thanks, Charlie

[vortecpro]

Do you have the uncorrected numbers?

I was assuming the heads are stock and flowing about 240 cfm@ .460” lift, that 507 hp is much closer to 250 cfm it would seem.

472 observed HP @ 900 feet elevation, 29.10 baro, derived from the first sheet posted.

[MadBill]

With only 0.0460" lift, the cam specs are surely 'advertised' rather than @ 0.050", so how can it possibly be still gaining power at over 6500 RPM?

[mt-engines]

I love these small cam builds. Mt, any porting work? Thanks, Charlie

Yes heads were ported, intake was port matched and the plenum blended.

[mt-engines]

Horsepower is just a number, and with a cam that small it wouldn't be very high. It should make decent torque. Somewhere in the 12s shouldn't be difficult if it hooks up. The combo is screaming for a good 3310, preferably one with the down leg boosters.

He bought my 80496-1 950 dyno carb. It picked up everywhere and allowed it to spin higher than planned.

[mt-engines]

Static compression should be in the mid 9s, depending on deck clearance.

Pistons were .012 in the hole .027 gasket

[rfoll]

Static compression should be in the mid 9s, depending on deck clearance.

Pistons were .012 in the hole .027 gasket

I get compression at 10.3:1. I'm curious about the cam. With such small numbers you clearly have done your homework to achieve the HP numbers posted.

[Old School]

Is the cam 270-275 at .020 or .050?
Is .460 lobe lift or valve lift?

[Elroy]

Shaft or stud rockers?

[77cruiser]

Anymore specs on the cam & head porting.

[swampbuggy]

This is not a Racing Engine, i am quite sure the .460" is at the valve and the Duration numbers are "Not" @ .050" lifter rise. I believe what we are seeing here is an example of what a great Carb, Intake, and well prepped cylinder heads can do in spite of a small numbers Camshaft. Mark H.

[swampbuggy]

Remember, the more efficient the intake tract is from the carb booster to the bottom side of the valve seat, the less camshaft ( especially ) duration will be needed. I will say, if the net valve lift is " only " .460". that is a surprisingly small amount. Mark H.

[77cruiser]

Remember, the more efficient the intake tract is from the carb booster to the bottom side of the valve seat, the less camshaft ( especially ) duration will be needed. I will say, if the net valve lift is " only " .460". that is a surprisingly small amount. Mark H.

594 hp @ 6700 worth?

[bob460]

Where is the "ENGINE TECH"..........you post basic spec build and will not answer people with genuine questions........

I thought we are on here to learn and grow.