78 351M Motor Swap

[86Bronco]

Alright, new the site here, but not new to the bronco world.

Just recently bought a '86 with the 302 EFI, I have developed a slight Rod knock at about 5000 RPM, I want to swap this motor out and put in my 351M, I know that she will bolt right up into her, but what I'm really fighting in finding an intake that will fit and support my fuel injection......Any ideas will help, and If i cant get it dont, I will just wait a year and register it as a Collector, then I dont have to worry about the EFI and emission

 

[79bigbronco]

your 351M WILL NOT bolt right in you will have to change the trans. a 351W will bolt right in and you can use the 302 intake as well, also there is no intake available for an EFI 351M.

 

[BLADE262US]

79bigbronco is right your 351m will not bolt right in to your 86 for a couple reasons . 1 bellhousing pattern for a 351m is the big block pattern and a 302/351w/351c is the small block pattern 2 the motor mounts on a 351m are not like the mounts on a 302/351w/351c so you will really need to find a 1980 truck or bronco that had a 351m so you can get the frame mounts. 1980 is the last year of the 351M and I have only seen a couple of them . In fact a guy I know has a 1980 F150 with a 351M that caught fire so if he still has it I may be able to get ya the frame mounts . And yes a 351W will bolt in where the 302 was BUT the 302 intake will not fit the 351w and a 351w intake will not fit a 302 . The 351w intake is wider than a 302 because of the increased deck height . Also 79bigbronco is right there is no fuel injected intake for a 351M/400 they didnt live to the fuel injection years but it can be done if you really wanted too . The 460 did live to the fuel injected years and shares the same ditributor as a 351M/400/351C so there would be your EECIV distributor you would then have to have fuel injector bungs welded into your intake and would have to make an adapter for a throttle body to bolt onto the intake . For a computer you might get away with a computer for a 351W but youd have to get the cam specs from a 351w FI motor and then get a cam for your 351M that had the same or very very close to the same specs so the computer didnt freak out . Might be alot of work but it can be done if you really wanted too . /emoticons/[email protected] 2x" width="20" height="20" />

 

[86Bronco]

All I was really chasing was the intake side of this. When I said bolt right in, I meant that it will slide right in, When I pulled the 351M I took trans and all, I know that the bellhousings are different, So I put that in the Keep Pile. I believe that the Frame mounts are the same, dont quote me on it, but if I remember right, when I put that M in my other truck, I pulled mounts off a W, if not its no big deal, I have a FAB shop next door that will make everything that I need. I think I'm just going to find a way around all the emissions ******** in Colorado, and go back to my double pumper.