head swap
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head swap
I have a stock 77 302 in my truck. The stock heads have the 69cc combustion chambers. How much would it raise the compression ratio by putting on a set of heads with 60cc combustion chambers?
The heads are 351w D0OE. The reason for the swap is a cracked head and I gave $30 to a friend for the windsor heads.
The heads are 351w D0OE. The reason for the swap is a cracked head and I gave $30 to a friend for the windsor heads.
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I'm not sure of the specs...but you will need to get a different intake and or modify the existing...the to motors have differing deck height and as I was told you will ned to shim the intake to make i fit...I had plans to do this myself as I have D00E-C heads from my 351w boat motor that blew on me and an 87 5.0 going into the boat now..I thought it to be an easy upgrade for HP but then was told it's a headache....but it came from a speedshop who was trying to sell me alum heads so maybe he was yankin my chain.....
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From: Kiefer, Northeastern Okla
The Search Function is a wonderful tool. Type in compression ratio. Also read post #5 in http://www.ford-trucks.com/forums/sh...ad.php?t=72441. Lariat- consider your chain yanked......
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I have everything to put the heads on. Summitt sells the head bolt bushings which i have, so you can use the stock head bolts, or you can get new bolts with the washers from A.R.P. Felpro sells the correct intake gasket. The taller deck height on the 351 makes it wider and is the reason for the wider intake vs the 302 intake. The heads are identical except for the few small details. I did a test fit with the old gaskets and everything seemed to line up and fit properly. I was just wandering if it would raise the comp. ratio to much with the smaller combustion chambers on the windsor heads before i put it all together and needed different pistons.
bushings = http://store.summitracing.com/partde...5&autoview=sku
bushings = http://store.summitracing.com/partde...5&autoview=sku
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From: Kiefer, Northeastern Okla
Biggman- shouldn't be a problem as far as CR goes. I came up with 9.1 to 1 give or take just a bit. You'll probably have to go to premium fuel and play with your timing to stop the pinging.
Lariat- Yes, the Performer RPM will work, but I wouldn't recommend it for a boat, especially if it's very heavy. The RPM's designed to work in the upper rpm range, whereas the regular Performer would be a better choice for bottom-end torque to get you up and on plane better. However, I have a buddy that used the RPM on his boat, but he had to change props ($$$). I guess a lot has to do with what you're using it for. He doesn't ski, he just likes to go fast.
Lariat- Yes, the Performer RPM will work, but I wouldn't recommend it for a boat, especially if it's very heavy. The RPM's designed to work in the upper rpm range, whereas the regular Performer would be a better choice for bottom-end torque to get you up and on plane better. However, I have a buddy that used the RPM on his boat, but he had to change props ($$$). I guess a lot has to do with what you're using it for. He doesn't ski, he just likes to go fast.
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my boat is a 1975 hamilton jet boat...it planes in less than 3 seconds...or it did with the 351W...I actually had 3 skiers over 200lbs each up at one time...so it has plenty of jump....the original motor was 175 HP...so I think with this one...by the time I get the motor finished I should have much more than that and it will balance out..but i may have to change the impellars due to the stroger top end and the fact it may be over revving the ones I have...but who knows...sorry if i stole the thread....I assume the pushrod legnths will need to be changed as well......I am gonna have to go to a mustang shop to get them to set me up with the right stuff....I think this is what I'm gonna do..if I up the compression I up the power correct...I will just need to get the timing done right and run 94 octane...nothing new for me...my truck runs that stuff too...
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From: Beachville, Ontario
Does that 87 5.0 have the stock E7TE heads? I certainly was hoping you weren't going to use the D0OE heads, but I have my own reasons for that. 
Original motor as in the 351 at 175 hp or a motor before that?
Original motor as in the 351 at 175 hp or a motor before that?
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Apparently they rated the early 70's motors at 175...my boat was a 1975...so I went by those specs...but the heads aren't matching the numbers from a 75 motor so i assume the motor is older than the boat and was possibly sitting on a warehouse floor in NZ till they put it in my boat...it is the origiunal motor apparently...but no worries..it would be too much work for me to put those heads on my motor now...all is installed and just waiting for the ignition and carb.,..
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Originally Posted by 02 LariatFX4
Apparently they rated the early 70's motors at 175...my boat was a 1975...so I went by those specs...but the heads aren't matching the numbers from a 75 motor so i assume the motor is older than the boat and was possibly sitting on a warehouse floor in NZ till they put it in my boat...it is the origiunal motor apparently...but no worries..it would be too much work for me to put those heads on my motor now...all is installed and just waiting for the ignition and carb.,..
but I think I want gt40P heads instead...
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From: Beachville, Ontario
I think the 75 heads had smaller valves and bigger chambers, therefore less power. Need to find specs on 69/70 351w....
nhra tech blueprint specs have a 2 barrel 351 with those heads from 240-250 hp. Doesn't list a 4bbl 351w for whatever reason.
Also, do you have a carb lined up already for the boat?
Talk about hijacking a thread.....
nhra tech blueprint specs have a 2 barrel 351 with those heads from 240-250 hp. Doesn't list a 4bbl 351w for whatever reason.
Also, do you have a carb lined up already for the boat?
Talk about hijacking a thread.....
Last edited by loudfords; Jun 20, 2006 at 11:42 AM.
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From: Kiefer, Northeastern Okla
This thread just begged to be hijacked, huh. Gotta agree with loudfords on the E7 heads. Read these:
www.thumperoforangepark.com
www.diyporting.com/E7p.2html
Pete
www.thumperoforangepark.com
www.diyporting.com/E7p.2html
Pete
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From: south louisiana
Originally Posted by 02 LariatFX4
Apparently they rated the early 70's motors at 175...my boat was a 1975...so I went by those specs...but the heads aren't matching the numbers from a 75 motor so i assume the motor is older than the boat and was possibly sitting on a warehouse floor in NZ till they put it in my boat...it is the origiunal motor apparently...but no worries..it would be too much work for me to put those heads on my motor now...all is installed and just waiting for the ignition and carb.,..
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Originally Posted by baddad457
BIG mistake swapping out a 351 to put in a 302 in a jet boat. It ain't the hp rating you're looking for there, it's the torque. Most 70's jet boats came with big blocks in the 70's and 80's, just for that reason. If you were getting up on plane in 3 seconds with the 351 before, expect double that with a 302, if it even will. It takes a lot of torque to make the impeller squeeze the water thru the jet. Water does not compress.
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From: south louisiana
What 6 cylinder engines ? Most I know of (straight sixes) generate more bottom end toque than a 302. Want a 302 with max torque? The very last ones (here in the U.S.) were the 94-97 Pickup/van 5.0's. The camshaft was their secret. Hyd roller, called the F4TE. Ought to work well in a boat too. Got one in my Ranger with a Ford high rise A321 intake and Holley carb. Power from idle to 6000 rpms. Makes enough torque that it'll over power/torque stock heavy duty clutches. Specs: 256/266 advertised duration, .445/.473 lift with 1.7 rockers, 116 LCA.