Which heads are better?

[Another Fastback]

On my coupe/ fastback conversion I have a complete 289 C-code with 75K on it and was running before it went under the bench,I am going to start tearing it down to send out and get the machine work done to the block/crank/pistons/heads and was wondering I have a set of '86 5 litre heads of of a LX my son in law gave me, are they better or worse than the originals? putting the car back together some what mild with the AOD and 4barrel, I have a local guy who will take a 9" housing w/ the ham in it and also take the 8" axles and shorten the 9" to the 8" width pretty reasonable,thanks,Pete

[madstang78]

you will loose compression with the e7te heads. I am not sure if they flow enough cfm to make up for the compression drop.

[beechkid]

If the 289 heads are the very early models, with proting, they will flow/perform very nicely! The (what I will call) later models with the smog bumps in them, they will flow good as well but do require more labor/machine work which is when you get into the question- is it just time to buy a set of aftermarket heads. The mid-80's stuff...all smog related that is not any better than what you have now.

[Renegade600]

The e7 heads will have too much chamber (64cc) and will lose too much compression on a 289.... the e7 is really not a great head anyway.

If you are not buying aftermarket heads, I would seriously consider porting your 289 heads, or have them ported... good bang for the buck....
Tom

[happystang]

GT40 heads off an explorer are very good heads and cheap, the e7's aren't the best. If you stick with the 289 heads definitely focus on the exhaust ports since they're somewhat tiny.

[wheelsup351]

i would go with the original heads. if i recall correctly, the 86 heads are NOT e7 heads, they are e6 heads.

the e7 heads are better, but not "that much" better and may need some relief in the piston to work.

[wheelsup351]

again, if i recall correctly the e7 head was used from 87 to 95. the 86's had e6's and the 85's had the e5's. 86 was the first year that all mustangs (stick and auto) were fuel injected. all were mass air cars after 87 i believe. so there were subtle difference in things like that.

[Paul1958]

1986 Mustang 5.0L used a one-year only 'E6AE' head which featured a masked intake valve/high swirl combustion chamber and is NOT recommended for high performance applications due to somewhat restricted flow. The 1985 'E5AE' or 1987-1995 'E7TE' heads (which are virtually identical) would be a better choice if you are limited to stock type 5.0L heads. If a choice between the 289 and the 86 5.0L heads I would go the the 289 heads.

[frdnut]

I would use the 289 heads.

[Huskinhano]

Originally Posted by Paul1958

1986 Mustang 5.0L used a one-year only 'E6AE' head which featured a masked intake valve/high swirl combustion chamber and is NOT recommended for high performance applications due to somewhat restricted flow. The 1985 'E5AE' or 1987-1995 'E7TE' heads (which are virtually identical) would be a better choice if you are limited to stock type 5.0L heads. If a choice between the 289 and the 86 5.0L heads I would go the the 289 heads.

The E5 heads are different from the E7's. The E5 has 69 CC chambers and very restrictive exhaust ports. They are basically the same as the 77 to 84 heads but were altered slightly to allow installation and removal of the new roller tappets. installing early anything heads on a roller cam motor the tappets better be in first. They can not be installed or removed with the head in place.

[supershifter2]

well, i always thought my other head was better !

[csouther]

I'd look for a used set of AFR heads with smaller chambers 165 or 185's

[madstang78]

I had my 289 heads worked over. Larger valves. Ported screw in studs etc. no idea what they flow though.

[6t9mach1]

If you are looking for a performance upgrade and your current heads need reworked its usually just as cost effective, and sometimes cheaper, to go with an aftermarket head. Performance, aftermarket heads will give you room to grow in the future if you wish. This is the path that I would suggest.

[bartl]

Depends on what you are doing with the 289 block. The actual CR of a 289-2V is about .7:1 less than advertised so you are really in the 8.4-8.5 range to begin with with heads having a 53.5-54.5cc chamber. Yes, the '86 heads are junk, so much so that they continued on the 5.0 non-HO applications in passenger cars until they went modular. The E5TE/E7TE-PA heads are around 61-62cc so you'll be dumping your CR by another half-point over stock 289 heads. If you're not going to do anything with the bottom end I'd stick with either the stock heads or an aluminum aftermarket with similar sized chambers. Another option would be a milled set of GT-40's (65cc) or GT-40 Cobra's (59cc) or if you don't mind the exhaust manifold choices, a set of GT-40P's (60-61cc). If you ARE going to replace pistons anyhow, then going to a flat top with the later iron heads is a decent idea. If you're into the DIY stuff you can always port & port match the original 289 heads and increase the valve sizes to 351W size (1.84/1.54), screw-in studs, etc., but many folks simply choose to buy a ready-to-run head off the shelf to make the process simpler.

Here's a nice article on making power on the cheap from a 289/302.. 400 hp 302 Small-Block - Mustang & Fords Magazine