got this from the internet when thinking of doing a 351 swap myself...
cant find the link now :(
but saved it as a word doc anyways
KEEP IN MIND THESE NOTES ARE FOR LHD BLOCKS
(things will need to be changed...but not exactly
as they suggest)
The 351 block and a 302 block are of very similar cast. Which means all trannys will interchange. Heads, timing chain, timing cover, water pump, accessories and internals like cam and lifters will also fit. Below is a checklist of things that you will need to do to make the 351 swap into your Fox body 302 Mustang.
1) You will need a new oil pan and pick up tube. Sold by FMS through Summit, Part number: FMS-M6675A58 - $131.95
You'll need a Falcon SUMP
2) The Flywheel and Harmonic balancer are balanced to 28oz. instead of 50oz. like on late model 302's. You will need to obtain a 28oz. flywheel and balancer.
Better look into this
3) The lifter valley on a 351 is wider. This means you will have to change your intake setup. If you have a Cobra intake or a TFS intake now, both companies sell just a lower intake for the 351 to match the upper intake you already have.
4) If you want to keep your A/C and power steering you will need a new accessory bracket for the 351. FMS also sells this through Summit, Part number: FMS-M8511B351 - $49.95
may have to fabricate something to suit AUS RHD blocks
5) The 351 will also sit a little higher than the 302 in which 302 headers will not reach the H-pipe. Many companies sell 351 swap headers for this application. I prefer the BBK ones through Summit, Part number: BBK-1511 - $219.95
Dunno if they will fit a Falcon
6) Clearance off the stock hood with the 351 sitting higher will be a 50-50 thing. I have seen a 351 sit underneath a stock hood before. Most of you will need a cowl hood to fit if your motor mounts are fairly new and still very stiff. If they are old I do suggest new ones.
Body work may be required
7) The distributor is also different from a 351 to a 302. You can obtain one from a 5.8 FI truck (if you are keeping FI).
should get one with the motor?
8) A spacer will also be needed for the crank pulley for proper alignment of the belts. FMS sells this crank spacer through Summit, Part number: FMS-M8510B351 - $34.95
should be cool
NO LONGER AVAILABLE