NOS 427 SOHC cam spec question

[338Raptor]

I just purchased a NOS 4v iron Cammer that the previous owner modified with 10 to 1 compression and different cams.  Other than some inter coatings, better carb, and electronic ignition the rest is stock. The motor currently is setup with 30 degrees total timing (which seems a little low) And the best I can tell from his notes the cams are advanced 2 and 4 degrees. His reason for these changes was to make the motor more streetable and pump gas friendly. I’ll send the cam card in the next post. I believe the cams he used are very close to stock.

My question is how much power do you guys think the motor is making?

[338Raptor]

No luck uploading a picture of the cam card.

Crane grind: CCR-570

Intake .570 lift at valve
Exhaust .570 lift at valve

                     Open.     Close.      Max lift.     Dur.
Int @.021   36 btdc      74 abdc.                    290
Exh @.021. 84 bbdc     26 atdc.                     290

Int. @.066   15 btdc    53 abdc.   109 atdc    248
Exh @.066   63 bbdc     5 atdc.    119 btdc    248

Remarks: the above reflects zero lash

[ToddK]

My engine was dynoed in a very similar configuration, although it does have a 4.00” stroke crank giving 452 ci, and my cams are 252 @0.050” and 0.582” lift. It has 10.3 to 1 static compression, and was run with a 750dp and 29 degrees total timing to suit 93 octane pump fuel. It made 553hp at 6300rpm. The heads are early iron heads, and pretty close to stock.

I have since changed the intake manifold to a Dove 8V Tunnel Wedge and a pair of 780vs Holleys. I haven’t had it dynoed in this configuration, but it certainly feels a lot stronger to my butt-o-meter. If you read any of the test literature from when these engines were released, they all state the 4V intake manifold suffered from poor distribution between cylinders. The factory 8V intake increased the hp by around 40hp.

[jayb]

I think 550 HP is probably about right.  30 degrees total advance is about right too, the most I've had to go on one of those engines is 32 total.  They are prone to detonation with more ignition advance.

[Autoholic]

Ford's crate engines were stated to make roughly 550 hp and 490 lb-ft for the single carb, 620 hp and 510 lb-ft for the dual carb. This comes from their SAE paper on the development of the SOHC.

[wcbrowning]

Those OEM SOHC engines were higher compression than the original poster's engine, I believe.

Ford's crate engines were stated to make roughly 550 hp and 490 lb-ft for the single carb, 620 hp and 510 lb-ft for the dual carb. This comes from their SAE paper on the development of the SOHC.

[338Raptor]

If the OEM engine had 12 to 1 compression and made 550hp and my engine now has 10 to 1 with cams that are close to stock. I’m guessing I have a reduction of 6-7%.
So maybe it makes 500hp now?
Agree or disagree??


I guess I need to put it on a chassis dyno and quit guessing. 

[WConley]

My original iron SOHC (unmolested) worked out to about 10.7:1 compression ratio with the original TRW pistons.

There's a bit of misconception that all of the series-produced SOHC engines had 12:1 compression.  From what I have learned, the early examples did indeed run a number like that.  The later 1966 "Street" series Cammer engines had a more pump gas-friendly compression ratio.  My engine bears this out...

[338Raptor]

If the OEM engine had 12 to 1 compression and made 550hp and my engine now has 10 to 1 with cams that are close to stock. I’m guessing I have a reduction of 6-7%.
So maybe it makes 500hp now?
Agree or disagree??


I guess I need to put it on a chassis dyno and quit guessing.