Is it possible to look at a motor spec sheet and make a reasonable HP Assessment?
 

Is it possible to look at a motor spec sheet and make a reasonable HP assessment?

I admit this technology goes over my head (but if you want to talk software development you're on! :-) ).

So, 2 questions;

1) How would you translate the following specifications into HP?

2) Do you see any low hanging/economical fruit that would bear a notable return in HP?

One thing that came highly recommended was to swap out the exhaust manifold and risers for those from a 496...those parts are "in the mail".

So here is the motor description I can provide :-)


*1986, MIE/340 (7.4) 454 Big Block
Dip it and hone the decks and cylinders (the cylinders did not need to be cut and are standard bore)
Block was detailed with all casting debris removed
Stock seasoned crank (polished)
Reconditioned connecting rods
ARP Rod bolts
.210 Domed Speed Pro pistons and pins. (should make it 9.38 to 1)
Molly piston rings
Federal Mogal bearings (cam, main & rod)
Cloyes true double roller timing chain
Crane #132561 hydraulic cam--Duration Advertised: 298° Intake / 306° Exhaust Duration @ .050'' Lift: 228° Intake / 236° Exhaust Valve Lift w/1.7 Rockers: .530'' Intake / .551'' Exhaust Lobe Separation Angle: 114°
Crane #99277 lifters
Comp Cams High-Tech pushrods #7954
Completely refreshed Chevy 14096188 heads / 454 Open / 118cc / 3angle valve
Comp Performance Valve Springs #911-16
Pioneer head bolt sets
ARP 1.90 rocker studs
Melling H/V oil pump
Melling HV oil pump shaft.
CrossWinds BBC R2 AIRGAP INTAKE
JEGS 15951 - Mechanical Fuel Pump
Pro Comp distributor
Super Stock coil
8mm Accel Hi performance wires
New single wire alternator
Mini (gear reduction and fully marine) starter
Edelbrock 750 Marine carburetor
14" Edelbrock air cleaner (with K&N marine legal filter)
Brass freeze plugs
Stainless steel bolt set
Sherwood motor mounted raw water pump.

I am no expert by any means at all but i think that it is safe to assume that because you are basically reproducing a mercruiser 420 mag motor that you can expect to see somewhere between 420-470 horse with the addition of the upgraded exhaust, intake, and carb. The cam you are running is a 420 cam so depending on your compression ratio its going to be similar.

Yeah, for all intent you are copying a Merc 420.
Not sure about the intake, but assuming it's as good as a GM hi rise dual plane, then you're looking at 400-440hp if tuned properly.

I would bore notch the block and zero deck it.
I would make certain that you run a squish height between .040" and .050"

I see good rod bolts, but if you run the stock cast rods, make sure you polish the beams. I would prefer to see you run forged rods.

Regardless of what rods you run, you will need to balance them, and also balance the entire rotating assembly because your pistons are heavier than stock.

Speaking of pistons, you will probably be better off with flat tops once you zero deck the block and tighten the squish as described above. Running a tight squish with those domes may put you at too much dynamic compression. What is the dome cc? Are your heads cc'd at 118 for sure, or is that just what they are "supposed" to be? Need both numbers for accurate CR calculation.

M

fixx
 

chevy rods are forged..

Like was said....about 420-440hp. Its basically a merc 420 clone with a little more compression.

Granted, but many of the 454's got the passenger car rods with the 3/8" bolts. A bolt upgrade is mandatory for performance use, but the better 7/16" rods or the dumptruck style "thumb" rods are an even better inexpensive choice.

MC