Hi guys. Looking to bump up the hp/ torque on my 89' f150 custom 351w EFI. I will be converting from speed density to MAF to allow for a cam upgrade and upgrading injectors also. I was planning to put AFR165 heads on and keep the flat tappet system, but what flat tappet cam would everyone recommend using with these heads and stock bottom end to bump power to around 350hp with long tube headers? If anyone has similar setups/ experience that would be awesome 👌.

 

MAF is a thing of the past on these. Mega squirt is the new thing, Stinger has a drop in for these

I would buy bigger heads. 170-185cc area, TFS Twisted Wedge get my vote. Cam size will depend upon your powerband wanted. Long runner plenum will limit wanting huge camshaft...think GM L98

Keeping it EFI it seems. If so, need to port out that stock intake and slap 302 upper on it for flow. Look at a stroker kit if you have to turn your crank and resize the rods. Might cost basically the same.

 

Mustang MAF computer (A9L, A9P) would still be set up for the same 19# injectors so that doesn’t get you anywhere. You could try to use a Mustang Cobra (X3Z) computer and mass air meter which used 24# injectors. Just because you are changing the camshaft doesn’t necessarily mean you have to ditch the SD system. What cam(s) were you looking at? The other bad part is finding a good flat tappet cam since the quality is not good nowadays and roller retrofit kits are very expensive. The cam and heads would be out of range for SD and might be too much for the Mustang MAF computer too. The Stinger PiMP computer is tunable and retains the SD system but allows you to either use batch or sequential fuel injection if you go with the “xs” computer.

 

I did a 165 AFR build on a stock roller cam 351 w/ long tubes and loved it for the ability to lug up a hill in od without downshifting. The 4 speeds of the day, with the giant gear spreads, make it hard to choose between the smaller heads vs 185+ but any load out back means it'd be downshifting no matter what......so aside from rolling empty / light load, I have go agree with everything Hit Man said above.

 

I have recently swapped a 351w into my truck it originally had a 300 i6. It’s a 5 speed manual. It’s running a 3.5” sky jacker lift with a 3” body lift on 35’s.( looking to get a proper lift soon).

I am looking to re gear it and also add some power upgrades. Hoping you guys can lead me in the right direction and help me out