351 REPLACING A 302?
Senior User
Joined: Aug 2001
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351 REPLACING A 302?
I have a '93 F150 with the 5.0 EFI. I want to put in a 351c.i. using the 302 heads and cam. I am told that this will eliminate any computer problems. We also think we have the intake manifold problem licked by machining some "spacers" so that the narrower 302 intake will fit the taller and therefore wider 351. We will also use the 351 push rods. WILL THIS WORK? OR IS MY USUALLY MECHANICALLY ADEPT BROTHER-IN-LAW GONE OVER THE EDGE ON THIS ONE?
HELP!!!... ANYBODY!
HELP!!!... ANYBODY!
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Joined: Jan 2001
Posts: 56,980
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From: Virginia
351 REPLACING A 302?
Yep, he's gone over the edge! What would be the problem with using the 351w heads? You can install the 302 cam in the 351w if you are really worried about it, but if the 351w has a stock cam, it should work. You may have to switch the sparkplug wires around depending on what cam you use.
Why re-invent the wheel? Is the lower fuel injected intake for a 351w, that hard to find? While your at it, check the fuel injector size of the 351w. May be bigger. You might want to trade your 302 computer in for a 351w. Probably calibrated a little different.
Why re-invent the wheel? Is the lower fuel injected intake for a 351w, that hard to find? While your at it, check the fuel injector size of the 351w. May be bigger. You might want to trade your 302 computer in for a 351w. Probably calibrated a little different.
Senior User
Joined: Jun 2000
Posts: 458
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351 REPLACING A 302?
Heads are probably the same anyway(depending on the year of the 351) except for the bigger bolt hole size. (the 302 will be 7/16" vs. 1/2" for the 351) Injector size is 19 pounders, even the 351 lightning uses 19 pounders. 351 EFI bottoms are plentiful at the bone yard and bolt right up to the 302 upper.
If you're going to do this get GT-40 heads/intake, Lightning cam(roller retro may be required)and find a Lightning EEC(they are speed density like your truck)
Push rod legth is critical with the pedestal mount heads. I can run you through the adjustment if you're interested.
If you're going to do this get GT-40 heads/intake, Lightning cam(roller retro may be required)and find a Lightning EEC(they are speed density like your truck)
Push rod legth is critical with the pedestal mount heads. I can run you through the adjustment if you're interested.
New User
Joined: Feb 2002
Posts: 18
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From: Lenexa USA
351 REPLACING A 302?
if I rember correctly the push rods are longer in the 351 (taller deck) and the lobes on a 302 cam would work fine for a 302 but the 351 is a larger engine and would need a little more lift to net the performance youre expecting from a 351. the heads should also work BUT once again there is the problem of compression ratio. the static compression ratio of a 93' 302 is 9.0:1 if you put 302 heads on a 351 the compression ratio may exceed 9.5 :1 and that means premium fuel and more money spent on gas. to top it off I would check to make sure that the water jacket ports on the block to head mating surface match I'm sure they do but check twice cut once.....
