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Old 11-17-2013, 06:32 PM
rcasonbbf rcasonbbf is offline
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Default cyl head specs /actual not from a book

What r the actual specs of the scj and PI iron heads. Valve size, port sizes, chamber size... differences?
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Old 11-17-2013, 07:24 PM
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mp40 mp40 is offline
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The CJ/SCJ had 73.5cc's

The CJ/SCJ heads feature 2.25 intake, 1.75 exhaust valves.

Screw in studs. Bottle-necked non adjustable 3/8" top/7/16 bottom studs for the early CJ and the adjustable 7/16 for the SCJ.

Guide plates (for 5/16" pr)

Spring seats (cups?) and machined/hardened steel retainers.

The intake ports on the CJ/SCJ where of course large 2.86 x 2.12 with 2.24 x 1.32 ports for the exhaust.

The P.I. heads are very close to the CJ/SCJ.

With the exception of the ports being cast smaller at the port openings. 2.20" x 1.93" intake with 2.06" x 1.31" exhaust

Their intake valves being reduced to 2.19 dia.

Their cc's being upped to 88 to 90 or so.

They have the same screw in studs guide plates and spring cups as the CJ/SCJ features.

I think, in many ways the P.I. heads have better valve bowl castings and from what i have seen the P.I.s are far better for the street than the CJ/SC heads.
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Old 11-17-2013, 11:45 PM
68xr7cat 68xr7cat is offline
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D0OE-R heads are 2.245" intake and something like 1.71 - 1.72 on the exhaust. PI intake ports can be opened up for the most part to CJ spec. with a lot of grinding. They not just different in size at the entry. Early CJ heads had adjustable valve train and all SCJ were adjustable.

IMO D0OE-R heads will stomp a D2OE PI head and I don't buy into that better on the street. On a 429 may be able to make a case, but a 460 and up no. I'd say PI heads can still be found reasonable cost and can be more cost efficient to do up over a D3VE or D0VE with large valves. All depends on cost of cores.
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Old 11-18-2013, 08:07 AM
jeffgfg jeffgfg is offline
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Back in the 70's Ford had their "Power parts" program, and published a guide for the 429-460 using factory parts. Their advice for maximum power was to fully port and polish DOVE heads, install large valves. they also used a SCJ cam retarded 8 degrees.This was to replace the CJ/SCJ heads. The dyno said that this was the correct way to go as it made more power. They said that the SCJ heads flowed too much on the intake. I almost did this with my SCJ torino. I realize that with today's information and parts you can do alot better. It would be neat to actully do this with an engine and see what power could be made and if it matched what Ford made. Just my 2 cents.
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Old 11-18-2013, 08:27 AM
rmcomprandy rmcomprandy is offline
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Depending upon your intended maintenance schedule and how much you wish to push the envelope ... An NHRA 429 Super Stock 429 engine using production valve size and port volume SCJ heads will be in the 850 horsepower range.

That in no way reflects the purposes of a street engine though.
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Old 11-18-2013, 10:28 AM
68xr7cat 68xr7cat is offline
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Quote:
Originally Posted by jeffgfg View Post
Back in the 70's Ford had their "Power parts" program, and published a guide for the 429-460 using factory parts. Their advice for maximum power was to fully port and polish DOVE heads, install large valves. they also used a SCJ cam retarded 8 degrees.This was to replace the CJ/SCJ heads. The dyno said that this was the correct way to go as it made more power. They said that the SCJ heads flowed too much on the intake. I almost did this with my SCJ torino. I realize that with today's information and parts you can do alot better. It would be neat to actully do this with an engine and see what power could be made and if it matched what Ford made. Just my 2 cents.
I believe they were talking modified D0VE to basically stock CJ. Retarding the cam 8 degrees will kill the bottom end too.

I don't know anyone who back in the '70 and '80 that raced with a D0VE head and then moved to a D0OE-R head that said they slowed down. I suppose there may be someone. What I do know is they did not have intake manifolds that could keep up with a ported D0OE-R and even today the best CJ heads can use a better intake manifold.
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Old 11-18-2013, 06:27 PM
jeffgfg jeffgfg is offline
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Yep you have to remember that back then parts for 429-460's were scarce we only had ford parts to deal with mostly. This was for a street engine and as listed this was the "top" option. It was listed for those with SCJ heads to remove them and install the ported doves. My SCJ sat for almost a year because we couldn't get pistons. Everyone said they had them but couldn't produce them. I still wish I had that car. Sold it not running with the engine tore down. Back then everyone laughed at my car because they thought it was a dog with a "boat anchor" motor, it surprised lots of people. Where I was from people were pulling 429 CJ's and putting in 428's cause they thought they were faster. I wish I had invested in the CJ/SCJ's instead of the 427 Tunnel port!!!
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Old 11-18-2013, 09:11 PM
68xr7cat 68xr7cat is offline
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Yes very true. Had the total performance era not come to a close when it did the 385 series would have ruled. The FE had 10 years of well financed factory development under its belt by the time the 385 series came out.

A good friend bought a Boss 429 Mustang new in 1970 and made it into a drag car. I recall how he would say all the good parts and information went to a select few. He never was able to tap into its true potential. Still was an impressive piece.
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