'93 351w Q's
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Mountain Pass
Joined: Oct 2000
Posts: 180
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From: Backwoods Massachusetts
'93 351w Q's
Hi all,
Have 93 motor Holley 650, Performer, RV cam, roller 1.7's, and long tubes. Seeking more torque, I have some old D0 heads with quenched chambers and screw in studs.
What is original compression ratio on a 93 truck 5.8? Are the pistons flat-top or dished?
Is the D0 swap a good idea? Also, how about long tubes vs shorties or tri-Y's (my current headers have rusted out) - what's best for bottom end torque?
Thanks for any/all opinions!
- Jeff
84 Bronco XLT, 151k 351w/c6 redone '95
Have 93 motor Holley 650, Performer, RV cam, roller 1.7's, and long tubes. Seeking more torque, I have some old D0 heads with quenched chambers and screw in studs.
What is original compression ratio on a 93 truck 5.8? Are the pistons flat-top or dished?
Is the D0 swap a good idea? Also, how about long tubes vs shorties or tri-Y's (my current headers have rusted out) - what's best for bottom end torque?
Thanks for any/all opinions!
- Jeff
84 Bronco XLT, 151k 351w/c6 redone '95
Senior User
Joined: Feb 2001
Posts: 155
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'93 351w Q's
I have a 351 out of an 85, and I know there are some differences between these year models. However, I will tell on my engine the pistons are down the hole roughly thirty to fourty thousandths, and are a cupped piston (13cc I think). Since you are already carburated, I would go with the early heads. I am pretty sure that those DO heads are not compatible with the later stock injection systems.
Rich
Rich
Senior User
Joined: Jan 2001
Posts: 326
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'93 351w Q's
If your looking for more lowend torque, go with the tri-y headers. They give the best lowend torque. Also, if your looking to change intakes, try to find one with equal lenght runners, this will also improve torque.
RCC
RCC
Cargo Master
Joined: Aug 2000
Posts: 2,931
Likes: 12
From: SW Michigan
'93 351w Q's
Batch, I have never worked on anything that new but do remember putting some C9 heads on an 89, your case should be about the same. Ford started useing the same head on 302s and 351s in 1979, unfortunately they picked the 302 style- this meant smaller valves and ports (too small). The early heads also have an extra pair of manifold bolts and 'L' shaped water holes, the new heads have a big square water hole, use some good felpro gaskets intended for the 93 and assemble the manifolds and gaskets carefully. The rocker setups may be different, I would run adjustables on the thread in studs if I were doing it. The chamber design of the early windsor heads is excellent, your mileage should be the same or better, and the better breathing will help power. Check to see that your D0 heads have been updated for unleaded before you put them on. Enjoy! DF
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