Thread: 700 hp 565 cid Bowtie

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Originally Posted by arock

I recycled this motor from my Hot Boat. Freshened it with some new parts and installed it in my 1973 Vega with built powerglide, 9" Ford spooled rear end and 8.5 certified cage.
I am running AFR heads, solid roller cam, girdles, dual 600 cfm carbs and MSD. Line lock and transbrake. I only run 10.5 to 1 compression so I can drive it on the street with pump gas. I have about 700 hp, which is more than enough in a 2000 lb car.
My question is: When I first fired it up, the headers turned cherry red in a matter of seconds. The cam was installed straight up. I retarded the cam 4 degrees and getted the hell out of the carbs. It now runs at 180 degrees in the garage for 30 minutes. That is where the cam was set while in the boat.
Does retarding the cam lower the compression? Cranking compression is 100 psi.

Compression in the cylinder does not begin until the intake valve closes, as the piston is coming back up the bore on the compression stroke. So, if the intake valve were closing at, for instance, 50 degrees after bottom dead center @0.050" tappet lift.........and you advanced the cam to close the intake valve at, for instance, 46 degrees after bottom dead center @0.050" tappet lift, then the cranking cylinder pressure should theoretically increase because less of the air fuel mixture that has just been forced into the cylinder by atmospheric pressure is being blown back out the "still open" intake valve by the ascending piston.

A cranking pressure of 100 psi would indicate to me that either the rings and/or valves are due for overhaul/replacement or the cam is much too large for the static compression ratio.......or both, making the motor a dog on the street. Crane Cams recommends a maximum 165 psi cranking pressure for use with pump gas and that's a long way from 100. I might expect 100 psi from a bone-stock flathead Ford, for instance.
http://www.vanpeltsales.com/FH_web/f...48_221-239.htm
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What you say makes a lot of sense when you brake it down step by step. The engine is a fresh complete overhaul. It was in my Hot Boat for a couple of years with a hyd. roller and ran great with an estimated 600 hp. It now has a 296/304 solid roller cam with .714 lift and 10.5:1 comp. ratio. Our pump gas in Cal is only 91. Maybe too much cam for this application. I an running AFR aluminum 335 heads with 112 chamber, Inconel valves, titanium retainers and stud girdles. Everything in the motor is first class. Calleys internally balanced crank, Manley rods, CP pistons and comp cam. New double roller timing set with no slop. I have an Edelbrock dual four intake with 2 600 cfm 1405 carbs that are jetted to hell.
The motor is in a Prostreet Vega Wagon with a build Powerglide, trans brake and 9" spooled Ford rearend. About 2000 lbs. I have about an hour of garage time on the motor now. I just put in the inner valve springs after cam break in.
What didn't make sense is on first install I lined up the dots on the timing set, (straight up) and did a minor check on cam timing. My bad for the short cut. Opened it up again and did a full degreeing process.
Cam card wants 22* BTDC @.050", I have multiple key ways on this timing set. No problem. But this setting shows 4* retard according to the timing set marks. Intake closes at 58* ABDC @.050". Dead on the cam card specs. There is no indication that my cam was ground with an advance in it. Seems like I am missing something. I have built 6 BBC in the last 15 years. All were Hot Boat motors that worked very well. I appreciate the advice.

My long reply did not show up. Took 15 minutes to write it.

Originally Posted by arock

My long reply did not show up. Took 15 minutes to write it.

HATE when that happens! And it's happened to all of us at one time or another. If I have a long detailed post that I want to do, I type it in the "Notepad" program ( any document program like Word etc. will work) and then copy it into here. Then if it gets lost it isn't so bad and easy to reinsert it. It isn't just here, I've had it happen on a few forums and not sure what happens... but it does happen.

Sorry for the frustration... try again?

Originally Posted by arock

My long reply did not show up. Took 15 minutes to write it.

I've had 'em blow out on me after an hours worth of writing. Makes me KILL mad.
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