Hello Everyone,

I've been hanging out in the 61-66 forum as I work on the disk brake and powersteering conversions on my 66 F-250. I finally received delivery of my 428 long block and want to see what you think of the setup and what kind of HP/Torque numbers to expect. I think I've seen that kind of feedback here before on other posts. So here are the specs on the 428.

Block Casting Number C6ME
Date code 5J24 (10-24-65)
Large 'X' sand cast on the back of the block. I belive this means high nickel content.
Bored over .0030 no sleeves
Oil Galleys drilled to 15/32
Hardened screw in galley plugs
New freeze out plugs
Deck surface was trued up.
Pistons 9.5:1 (expect 9.8 compression with truing of block deck)
Miladon 5 QT reproduction oil pan (front sump)
Millings (sp??) high volume oil pump
ARP oil pump driver

1U Crank
Main and rod journals turned to .0010 under stock

Detroit balanced flywheel

Stock piston Rods shot peened and balanced

ARP Bolts

Heads - C6AR-6090R
Stainless valves 2.02 intake, 1.56 exhaust
Hardened exhaust seats
New springs retainers and locks
Exhaust ports drilled for multiple bolt pattern

Ford Motor Sport multi-index roller chain

Holman Moody Cam
C3AZ-6250-AA
526 lift
298 duration (intake and exhaust)
Solid lifter valvetrain.


Intake C6AE9425H
Police Cruiser (Dual Plane)

Carburator - Reconditioned Holly 750 single pump
Manual choke vacuum secondaries.

This will at least initially be bolted to a MX cruise-o-matic.

Rearend is a 4:10 gear.

I'll add a Petronix elecronic ignition.

I think that covers it. Thanks in advance for the feedback!

 

Assuming headers, dual exhaust with mufflers, the closest cam from comps camquest software says:
cam is comp cam 280H, 280/280 duration, with .530/.530 lift.
346 HP @ 4500 rpm, and 454 ft lb TQ @ 2500 rpm
I tried adding high performance heads with stock ports/valves, added only a few HP/TQ.
Tried comps XE274H cam, again added only single digit gains, though personally I would use a split duration cam when using stock cylinder heads, as the exhaust flow is rarely 75% of the intake (the point where a single pattern cam works well).
I would suggest using high cfm flow mufflers from dynomax, etc. Their web site has a section on calculating the cfm flow you need for your engine size.
I would also lengthen the header collector length to 18 inches minimum (for high rpm) or 24 inches if you want more low end torque. There have been a number of articles verifying the benefits of more collector length.
I would block off the heat crossover in the intake manifold. A cold mixture is denser, and helps reduce detonation. I blocked mine off with 0.012 stainless steel sheet glued to the cylinder head, then mr. gasket 202A intake gaskets, they are softer than felpro, and squish down easily over the thin metal sheets. hope this helps

 

FEmtnmax - Thank you for running the numbers and offering suggestions for increased performance on this engine. I was not sure what HP and TQ to expect. I was hoping for better numbers but, who doesn't. I know I have much to learn on the whole subject.

According to one website those numbers are close to advertised stock numbers for a Police Interceptor 428 engine. (340 HP @ 5400 RPM and 459 lbs/ft at 3200 RPM). Based on data from the Holman Moody website I believe the C3AZ-6350-AA cam is the same one used on the 427 sideoiler. I guess for a streetable engine this is a moderate cam. I also thought that the solid lifter and PI intake setup would give it more gettyup.

The mechanic family/friend who does most of the maintenance of our family vehicles also does custom exhaust work. I'll share the information you provided with him when it's time to add headers. I appreciate your help.

 

The 428 PI was rated at 360 horsepower @ 5400. The stock 428 Thunderjet was 345 horsepower @ 4600 and 462 ft/pounds @ 2800. Of course they both had 10.5 to 1 compression to help the horsepower. All three engines ran hydraulic cams. The PI also ran stock 2.02" intake and 1.57" exhuast valves like the 390 and stock 428 had.