Ok, how much will I gain?

I have a 74 Maverick that I have been planning to put the 302 I took out of my 76 F100 for quite a while. The 250 I6 in it now is running less than an hour before oil fouling the plugs, so the time is sooner than I intended.

I have been reading and hearing of engine modifications for years, but I really don't know how much improvement I can expect out of what I can afford and am competent to do. When the engine was in the truck I had put a four barrel on an iron intake with headers. There was some improvement but it didn't make it a hot rod. An improved cam helped some more, but still...

According to the books, if I remember right, that 302 was only rated at 150 HP when stock and new. This is the list of mods I'm planning on for the rebuild and install:

500cfm Edelbrock 4bbl carb
I can go with an aluminum intake, but how much improvement will I see over the iron I already have?
Headers, probably the Hookers
The cam I put in the truck was a Crane Cam 130042 (has less than 20K miles on it)
“Dremel Tool” porting on the heads.

My goal is 250HP. Do I have a realistic chance of being anywhere close to that? If not what is the ballpark guess for where I’ll be?

 

find some e7 heads off of a 87-95 mustang. put the proper valve springs for the cam in the heads. also get either the mustang rocker arms or some pedestal mount roller rocker arms. that should easily get you 250 hp. the 76 heads are some really bad heads for making power. they are smog dog heads.

 

Probably exceeding my competence level. There is no one available locally with the experience necessary to help me do it, since I don't know what the proper valve springs, etc. are.

I won't be the one doing the main engine rebuild, but I could provide better heads if I knew what to bring to him. The block I'm going to use is from a 77 F100. I just found out the 76 has already been bored to .060" and not rebuildable. The 77 is a parts truck I acquired several years ago.

The shop that will do the rebuild work is willing to put in the cam I want, but they do not do custom hot rod work. If I brought them heads from a different year, they could use them, but they'll want to use stock valve springs and such.

 

what part of west texas are you in?

 

Just south of Abilene.

 

to do that you should remove the valves. once the valves are removed you have removed the springs. if you goto the cam manufactures web site they should have the recommended valve springs for the cam your using.
you should be able to find e7 heads all day long on craigs list for around 200 for the pair. even try posting an ad asking for the heads and you should get plenty of offers. if you were local i have a set that i would give away.

 

Just learned a new term to add to my of automotive "lexicon"!

 

Speaking of lexicons, what makes an e7 head an e7 head?

 

thats the first 2 digits of the casting number


located on the bottom side under the intake ports

 

If you do not already have the 500 cfm carb, go with a 600 cfm. If you already have a 500 cfm, then run what you have. If you are going to the trouble of porting and/or polishing the heads, ditch the cast iron intake and replace it with an aluminum dual plane one. If you are still using points and condenser distributor, you may want to think about converting over to electronic.

 

I had a 600 cfm on the 302 in the truck, seemed to be dumping too much for good throttle response.

The 600 cfm seems about right for the 351W that's in the truck now.

Will use an HEI distributor.

 

So an E7 head is one manufactured in '87.

What is the significance of that year of manufacture?

 

Any chance the carb is running rich and causing the plug fouling??? I bought a '75 with 250 years back that had anti foulers on all the plugs, turned out engine was OK just needed the carb rebuilt...

 

I just rebuilt the carb thinking that was the problem. Also pulled the valve cover and oil pan to clean out the sludge. Ran somewhat (not real good) for about 2 weeks before it quit again.

The only thing I could do to get it to run on more than 4 cylinders was clean the plugs, but it didn't take long to foul again.

I am not going to sink any more cash in the 250.

 

the 87 5.0 ho was the first year of that head. they used the e7 head on trucks mustangs thunderbirds and ltds untill those cars switched to the 4.6 mod motor. that motor was rated at 225hp in stock smog legal form.