must90

i am building a 351w for my 1990 lx and i was wondering which would be better to use, my stock 302 heads or 351w stock heads from 78. also i need to get a timing cover, do i need to get the one to match the year of the block or can i use a 302 timing cover(which year?) I plan on going fuel injected and i have been looking at intake manifolds. What is the cheapest route?

Arrid Extra Dry

wont be much difference in the heads, in 78 they didnt have alot of compression
aftermarket heads would be better

timing covers are the same, except on some fuel injection motors they blocked the fuel pump off
302, 351 same thing

cheapest way out, go to a junk yard and get one off of something like an 89 f250 with a windsor motor
but id go after market with that too
good luck

90mustang5.8

just use your 302 heads...a 302 and a 351 are almost the same thing

vristang

The head bolts on the 302 are a smaller diameter than the 351w bolts. In order to use the 302 heads, you will have to drill the bolt holes to .5"

If going efi, I would think the easiest timing cover would be one from an efi 302 application. This way you won't have to worry about capping a fuel pump mounting location on the timing cover.

For the intake I went with the Lightning GT40 lower, since I already had a Comp Cams Polymer upper for the GT40.
When I did the swap the Cobra/Lightning intakes were pretty decently priced, but that was several years ago.
I think there are better intakes out there now?

Good Luck with the swap,
jason