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Topic: Heads Question (Read 774 times) previous topic - next topic

Heads Question

If i put 351w heads on my 302 will it make a tdifference in power?
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1979 Mercury Cougar X R 7
White w/ Maroon Vynl Top
Maroon Interior
302 BIG HP IN PROGRESS

Heads Question

Reply #1
Probably not at all.What year heads.The heads from the 70's and up were the same between the 302 and 351....just the 351's head bolt holes are bigger and you have to use spacers for the heads to install them on a 302.Find a pair of GT40 heads.They can be found at decent prices and will be great for your engine.The EARLY 351 W heads are desireable,but they were also made for leaded fuels,so,you'd have to have new valve seats installed.Too much work when the GT40's can do the same thing.What year is your engine (5.0)?If it's a stock 5.0,non-H.O.,then go grab a set of E-7 heads from an EFI 5.0 pickup.They are the same E-7 heads the Mustang has and will help a little.What other mods are done to your 302?
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Heads Question

Reply #2
i think he's talking directly about the early W heads, everyone down south is c00ching them up left and right, especially in the pony community.  its actually making them easier to find.

Heads Question

Reply #3
I think the Gt40 heads were somewhat based on those early 351W heads.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Heads Question

Reply #4
Is it possible to do this vice versa? Can 302 heads work on a 351 by just making to bolt holes larger? I have wondered this for a while.

Heads Question

Reply #5
I have put 302 heads on a 351 but drilling out the bolt holes to 17/3c.  I did this on a 1976 Van in the hopes of improving MPG.  I thought the smaller ports and bump in compression would be good.  But it turned out it ran fine but I could see no difference.

But I think if you put 351 heads on a 302 you could loose power because the combustion chamber is bigger and you will loose compression.  The valve and ports are bigger but with the lost in compression I don't think you will come out ahead.

With all the aftermarket heads out there I think it would be better just to go to one of those.

TED

Heads Question

Reply #6
i had a set of edelbrock heads on my 351 but i swapped it out with a newly built 302 and i didnt kno if it would work
[SIGPIC][/SIGPIC]
1979 Mercury Cougar X R 7
White w/ Maroon Vynl Top
Maroon Interior
302 BIG HP IN PROGRESS