Hey guys i have a few questions I'm currently in process of rebuilding my 5.0 it's in a 92 f150 its SD I'm looking at getting some gt40 or gt40p heads I'm not sure what style I may be able to locate locally I intend on sending them to a machine shop to be cleaned and rebuilt I'm yet to find springs or other relative components but I'm thinking about putting the comp cams 35-249-8 in it I'm not trying to build any kind of power house but as far as I've been able to tell these are generally better performance than stock without needing anything major but my issue is I've seen some conflicting info about trans life/rear end with upgrades similar to this I don't think I'll be making any kind of crazy power but I think I'll be looking to be around 300HP so do I need to be looking at a trans upgrade or anything along those lines and is there anything I need/should do and or change in this setup I'm replacing just about everything my pistons and block are immaculate as far as my eyes can tell it has 220k on it I intend on sending it off as well to be cleaned and have everything checked I'm not afraid to change or not do something if it'll hurt more than help as this is my daily driver i don't particularly want to lose any reliability no major components have been purchased yet so any advice would be greatly appreciated as this is my first engine build I'm getting a bit lost in the numbers i can get any needed info on the block or any other relative components if needed

 

You should avoid the “P” heads unless you already have a line on headers that will work. Whatever spring the cam manufacturer recommends is what you should use. I think that is a typo and you meant Comp 35-349-8 cam? What transmission? Are there any issues with the transmission that sending more power through it will cause it to fail? The rear axle should be fine.

 

With 220k on it you will have some cylinder bore wear and taper
That means once the machinist measures those, you WILL be getting new pistons and a bore job
Good luck with the build
Maybe find a roller block
The machinist will probably balk about drilling and tapping holes in your block for a lifter spider
The bosses are not there for the spider bolts on the non-roller blocks
People drill and tap them anyway; I feel that is trouble waiting to happen

 

Pretty much a given that bores will need to be cleaned up

Unless it had been swapped out, the OP already has a roller ready block.

 

The Comp 35-349-8 produces 275-280hp with E7 heads so it will be well over that with GT40s... add 20%. I had that combo in my '90 with MAF and a TweecerRT so I could see what was going on, it pushed the 19lb injectors for all they are worth so you will have problems trying to run this cam with heads on SD.

 

the trans has no issues I don't have what model on me ill have to go get the numbers off the truck its an automatic idk if that'll help much but i can get the model off it today and my apologies I do meant the 349, all the cylinder walls are in surprisingly amazing shape no scoring or discoloration and still has clear visible crosshatching through all of them and no bur or any lip on the surface I'm yet to put a bore gauge on it to confirm there all okay. I'm fine with getting it bored and getting new pistons if need be, my biggest takes were possible intake issues maybe not providing enough air? and as someone else stated possible issues with the SD system I'm perfectly fine swapping the ecu with another style or type even custom programming one my issue is most of the newer solutions awwm to be quite costly and that's just not within the budget so if there's a cheaper alternative or if should just keep the engine more stock I'm fine with either

 

No.

There are no "cheap" replacement PCM options, the only one that is close to plug and play is the Stinger Pimpxs which has the transmission control capability you need.

 

I'll be that guy: think about a 351 swap and don't chase peak power numbers. A 351 will have a broad flat torque curve; which is exactly what you want for a truck.

 

I am the other guy: do a 347 stroker. You are already on the path for aftermarket EFI. Might as well go big on the 5L block with one of the best factory EFI intakes. Best of both world's IMHO.