lets talk turkey, mine was a stock longblocked 351w, upgrades over the years, edelbrock efi intake, 1.7 rr, kn intake setup, and the bbk 61 dual t/b , each on their own accord made slight differances. we'll see how she is now. with gt40p heads, and a pretty stout comp cam and shorty headers and 24lb injectors. best bang for your buck will always be gears! as far as header clearance i am running the fms truck headers and heres the 2 i had issues with

 

^^^ nice pics. thats basically what ive found, the shortys are a bit tough to get to work. one glance at the crazy shaped stock manifolds that ford used in the exploders lets ya know that the plug wires have a very small window through which to snipe the plug tips.

 

Depends what vintage engine you're working with, with a '94+ 5.0 or 5.8 I'd agree but with the earlier EFI motors there are big gains to be had with a cam alone.

 

thanks 89f2urd!

 

all i know is that i've driven the mountaineer several times and got better then expected mileage out of it, it may not be 17 but still the fuel gauge doesn't drop rapidly like most trucks i've seen. i was thinking about roller cam cuz of the benefits i've been reading but wanted to hear hands on experiences

 

....If your 351 is a 94+ model with a roller cam , the 302 HO cam works nice in the 351 , or something similar.....Lew

 

Holy crap Jk89CAT! That is a huge ding in your header for a spark-plug (top pic) Thats like halfway into the pipe.

I have also heard that longtubes are much easier to use with the GT40P heads.

 

i know it. its actually deceiving looking its actually not that deep, may bout a 1/4 of the area into the pipe , its also by the collector , but yes it is quite dimpled. used a mack piston wrist pin and a torch and a bfh!

 

How much of a compression bump is it for the gt40p heads. About .5 maybe.
If I pull heads I'm definatly gonna do a cam swap. And it will be roller. It's cheap to do and cams aren't that much more for what you're getting.
Roller rockers and valve springs are also on list.

 

yea it puts a stock motor to ~9.4:1, and the gt40p's can be milled to put the motor well past 10:1 without milling so much that intake milling is required also. which means its a pretty cheap way to bump compression. . .75 bucks is about the average that a machine shop will charge to mill a set of small block heads.

 

Hmm
I thought the 351 only had like mid to high 8 compression. I really only want low 9 so I can boost it without worry. If I had alum heads I wouldn't worry, but I don't really want to invest that kinda money.
Maybe I'll use a MLS head gasket to counteract some of the compression bump. Gotta think about this a little more. Or I'll just pop in a bigger set of valves into the stock heads and port them a little.
I just wanted a little gain until I got my blower intake built. But boost solves lots of inadequate flow issues. LoL

 

These EFI motors have about 8.8:1 with the stock 64cc heads so the small 60-62cc GTP heads will only bump that to about 9.2:1.

 

Perfect. We are on the same page then. I like that number for compression.
Good for na applications and ok for boosting still. I'm only expecting about 6-7 psi from the setup I'm putting together, but if it goes to 10 I'll have to figure out some more accurate tuning.

First though, is stainless longtubes, 2.5 mandrel bent stainless pipes into dual cats, into a magnaflow muffler and single 3" out the back with single side exit. I may even throw a resonator in there depending on loudness.
From there it will be valve springs and roller rockers and alum valve covers, with probably an intake spacer to clear the covers. (the gtp springs I have noticed are not ideal for 1.7 rockers and high revs)
Next will be mock up the blower intake. You guys will like how this goes, but it's a secret.
While blower intake is being milled and welded, gt40p heads will get worked on, and lower intake (spare) will be milled and ported to match the 5l truck upper intake (bigger ports like systemax intake)
I'm still driving the truck while this is being done. I believe that each step needs to. E tested and bugs worked out in between so you don't have all kinds of problems.
Then there will be a cam and head swap with the ported lower intake but stock 5l upper intake (no blower yet...sorry)
Once this whole combo is running mint, ill have the blower setup complete. Then it will be super fun.

I'm hoping most of this will work with speed density. I've done some radical things with the mustang sd setup. But if I have to swap to mass air, I'll do that at whichever step gives me drivability issues.

(yes I have a lot of spare parts laying around...don't you)

 

you suggested in another post that you'll be porting the lower to accept the 5.0 upper. . .

the 351 lower needs a ton of grinding to match the gt40 ports, and to remove the choke points in the intake runners (there are giant protrusions just inside the runner if you look from the head side). then there's porting the sharp radius where the upper bolts in order to straighten them up a bit (not such a sharp bend at the bottom). THEN massive grinding is involved to match the 5.0 intake that really cant be perfectly matched for a number of reasons. the largest reason can be seen by placing the 5.0 upper gasket on the 351 lower, some of the "very slim" parts of the gasket dividing the runners protrude into the 351 ports (it would be best, if not required, to use the 351 gasket and trim it to the new shape(s) after porting). another big reason is the direction of the runners in the 351 base vs the 5.0 base, the 5.0 runners are more of a straight shot due to its slightly raised design vs the 351's pancake. ive contemplated doing all this grinding myself, and i still might. however, if i planned on changing it in the future, noway no how would i spend that amount of time at the grinder just to replace it down the road. its A LOT of grinding.

the low 9's in compression ratio is still plenty safe to run a substantial amount of boost, safely on pump gas. also, you should def use a good quality MLS if youre runnin boost (you dont need an MLS to decrease compression). cheap peace of mind as you'd be minimizing the risk of a blown HG so commonly associated with boosted app's.

 

15 mpg might be possible in a 2wd 5speed with all the right parts and a 80lb old foggie driving