I am really confused now. I have an 87 351w HO that came out of a f150. I am going to be putting it in a 75 bronco. I want to focus on torque and power below 5000 rpm's. I need to decide if I want to buy gt-40y heads, or rebuild my stock heads. The machine shop says I will lose bottom end power, the head supplier says I won't, and think they will make a considerable difference. which one is correct. Is it a waste of money to buy aftermarket heads, but us stock exhaust manifolds?

Thanks

 

If your going to use the stock exhaust mainfolds I would not buy after market heads. Run the stock ones.

 

Well according to this website---->

http://home.isoa.net/~mharrisj/fordhead.html

The gt-40y don't flow much better than the gt-40p, so I would say with that in mind your not gonna lose much in the way of torque. I saw comparisons of E5/E7's (your heads) to Gt-40p heads with similar cams/combo and the torque increased overall across the rpms, and stayed the same at off idle or increased.

Also, after seeing that they flow similarly to the gt-40p I would not recommend purchasing them, unless your getting a deal. But thats my opinion, you could get similar results if you had your heads ported professionally or do some research.


Home porting webistes for the E5/e7 head (they are the same head except the e5 has larger combustion chambers and a larger thermactor bump) otherwise the ports are similar.

http://www.cmc.net/~xero/Mousesporting.html

http://www.mustangcentral.net/tech/e7.html

http://www.carbdford.com/tech/HeadPorting/porting.htm


sites for electric die grinders, carbide bits, and abrasive rolls. These sites also have carbide burrs for the dremel.

http://www.carbidebur.com/

http://www.harborfreight.com/

http://www.ruffstuff.com/

http://www.travers.com


places that will professionally port your heads and get them to flow better or equal to the gt-40p for $450-700 depending on company.

www.xsrcylinderheads.com

http://www.jlmcylinderheads.com/

http://www.hunterstyle.com/thumper/

www.powerheads.com these are cnc machined the others are hand ported

I don't know if its a total waste to use stock exhaust manifolds, you could always port them as well, but I would at least use some shorty headers, if not long tubes. They are rather cheap and would help the bottom end out. Something to think about, good luck

 

The GT-40P heads benefit from the spark plug location and the combustion chamber design, not so much the flow numbers.

 

If I understand correctly, the smaller valves give better low end torque. I'm certainly no expert, but have been looking at heads myself. Seems that smaller valves, are better on low rpms, but limit the amout of air/fuel entering the cyl. which, in turn, limit how many rpm's the engine can turn. My thinking is the 62cc heads with 1.92 intake valves would be a good combination for a "truck" motor, plenty of low end, and still breath well enough to turn 5500 to 6000 rpm without a big cam or large carb.

I'll leave the loud, rumbling, loping engines for the young guys. I want mine to make 300 hp or so, be quiet as a church mouse, and idle smooth as a baby's cheek. Should be doable fairly easy don't you think?

 

victorcharlie

Your stock heads could take you to 300hp. I am with RTM, if it were between the gt-40p and gt-40y, I might lean towards the P, unless the price is right, but thats my opinion. later, good luck

 

I was thinking about changing heads on my 85 351w with e7 heads but my desktop dyno showed no great power increase exept in the top end. My machine shop guy said porting them myself would be more cost efective and still get the power i want, where i want it, he gave me a set of e7's that were no good and told me to practice on them making sure not to grind away too much material and get into a water jacket. when I was comfortable with it i started grinding on my heads then took them to him and he said i did just about as good a job as he would have done (he said he would have taken out more material but praised me for playing it safe). the motor is a 351w virgin (4" bore), ford racing 290/300 cam, performer intake, edelbrock 600 carb, shorty headers of a mustang and produces 305hp and 385 ft/lb between 2500 and 3500 rpm so i think i did good.

just like the rest of the guys this is just my 2 cents worth

good luck

 

fordnut1985

Those hp and tq figures are they dyno or desktop dyno, if dyno, how did they compare to the desktop dyno? later

 

hey jw, they are desktop #'s but i do plan to put it on a dyno as soon as i get the cash for it. but the guy at the dyno shop says the desktop is pretty accurate with +/- 5hp

l8tr

 

fordnut1985


What you posted caught my attention, I have been asking ratsmoker in the performance engine building section, to run different cams with an identical setup, some with stock e7 and some with stock gt-40p (similar to ported e7), and he ran the A332 you mentioned with e7 and it barely broke 250hp. Even if they were ported it wouldn't increase by a substantial amount, IMO. NOT saying your wrong just saying, what I have information wise is conflicting. Here is the graph with the A332 compared to the Comp XE268H. Who know? I have to admit I like your numbers better , but I have to wonder. See what you think and lemme know.





If the graph doesn't show up for you, follow the link and go about half way down, bottom of graph has A332 and XE268. later

 

jwtaylor

i just looked over my stuff and it all looks good, the only thing i can think of is the airflow data i got is bad, i got it from a head shop they let me copy a test flow they did on a set of ported e7's. here they are, take a look and tell me if you think it is wrong or what

intake exhaust

test dia. 1.78" 1.45"
pressure drop 28.0 in/h2o

Lift CFM CFM
0.100 57 40
0.200 114 78
0.300 142 107
0.400 146 118
0.500 150 123

the rest of the specs

4.000" bore
3.500" stroke
valves 1.914 intake 1.511 exhaust
9.5:1 compression
600cfm @1.50 in/hg carb
dual plane intake
small tube headers w/ open exhaust
ford racing A332 cam

you can tell me i'm wrong, you might be right that is why i'm here :-)

l8tr JW

 

fordnut1985

I'm not saying anyone is wrong , I am just trying to be sure that what I have information wise, is accurate.

Actually the numbers you listed above are stock air flow numbers. One referrence to compare is the below link...


http://www.jason.fletcher.net/tech/f...a/castiron.htm

There was an article in MM&FF that had similar air flow numbers for stock E7TE heads.

The only difference between your combo and the one ratsmoker ran is I had mine listed as 8.5:1 compression and yours 9.5:1, and adding compression wouldn't make up the difference.

Check out the link and let me know what you think. Does that cam have a decent lope to it? later

 

My heads are stamped e5ae. Are these the heads that are the same as the e7's, but with a larger thermactor bump? How much are gt-40 heads going for, and can they be found?

 

Check ebay or different classified sections on mustang forums, you will definitely find a set of heads.

www.corral.net
www.stangnet.com
www.carbdford.com
www.50tech.com

there are probably more but I am sure you can find what your looking for in those links, under classifieds. You could check out local junkyards 96 and down explorer/mountaineer vehicles with 5.0 motors had gt-40 heads, and the 97 up mountaineer/explorer vehicles with 5.0 motors had gt-40p heads. If you pull these heads off to install on your 351w you will need the head bolts enlarged to fit your 1/2" head bolts, no big deal. Check around though, there are a lot of used heads floating around. Good luck

Yeah I am almost certain that your E5AE heads are the same as E5TE heads. The "A" stands for ford, which could be any vehicle and the "T" stands for ford truck, and they mixed and matched the heads any ways, so I would say with that in mind that is what you have. later

 

jwtaylor

i checked out that web site after i posted mine and i think that is where i got my info from. i couldnt find the sheet i copied from the head shop. I looked at your questions to ratsmoker and was wondering what brand/version of dyno he was running, mine is desktop dyno 2000. I have heard alot about it's accuracy but the guy at the machine shop said he uses it all the time and it is fairlly accurate. by the way i don't know how "loopey" the cam is cuz i havnt got the intake yet (it should be here friday). as soon as i can it is going on a dyno so i can see for sure what it will do you got my curiosity going now hehehe.

l8tr