Vintage Mustang Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
3,897 Posts
Discussion Starter #1
Last September I posted and ranted and debated with you all about the 351W heads water ports not matching the water ports on the older 302 engine block. Now, I have a nice little 1981 302 block and the block-to-head water ports match up perfectly. So I'm really tempted to mount those heads.

Question is this: Should I wait to use the 351W heads???

This is why:

1. The 302 runs. I am not going to rebuild the engine due to lack of funds at this time. I just want to detail it and get it in the car. All the support stuff to go with the engine, (clutch, batteries, drivelines, brakes, etc, etc, etc will cost aplenty anyway). So the thought being, get a basic engine in the car and rebuild a dream engine later.

2. If it were a matter of just installing the 351W heads and getting a performance upgrade instantly, I would do it. But a stock 302 has fairly low compression and the larger combustion chambers may lower compression further. I'm not sure I want to buy higher compression pistons (thus rebuild the block) or spend the $$ to shave the heads at this time. I would have to sacrifice buying something else that would help get the car going sooner.

3. Am not sure the 302 intake manifold would work with the 351W heads...

To buy new 1/2" head bolts, higher compression pistons, and the associated rebuild goodies, head re-work, intake manifold(?), would add up to a well over $1000 I don't have right now. Maybe I should wait, and not lose sight of the original engine goal.
 

·
Registered
Joined
·
38 Posts
Wait--an engine is a system that requires complementary parts to make it perform. Changing one thing generally does not help and oft times hurts. Lowering the effective compression ratio, distorting the flow of the fuel-air mass will probably result in an overall loss of power although you may have gains in specific RPM ranges.

Once you have pistons, a cam, intake manifold and headers then the heads will give you the performance. I guess the answer to this question is you should always wait until you have the total package other wise the engine will be a dissappointment.

Most of us don't have the patience to wait and rush into these things without planning what the finished product is supposed to be. Lots of guys will tell you one change made a big difference--either they had everything else and this last piece made it all work or they are just imagining huge power increases to justify all the unnecessary work they just did.

Good luck.
 

·
Registered
Joined
·
10,587 Posts
Save the heads for a rebuild....

the 351W heads water ports not matching the water ports on the older 302 engine block

Maybe I just learned why my early 289's and 302's ran so hard. The holes never matched up perfectly on those either.....
 

·
Gone but never forgetten
Joined
·
25,239 Posts
What kind of shape are the 351w heads in currently? You'll still use the 289/302 intake ... the 351w intake is too wide and won't work. You'll still use the 289/302 head bolts ... your block is still going to ONLY take 3/8" bolts. So the only thing holding you back is shaving the heads and getting method of taking the bolts from 1/2" holes in the heads to 3/8" holes in the block. There's a multitude of ways to do that. The oldest way is by just sticking some grade 8 washers under them.

My point is, that you could actually use the 351w heads right away for very little money. I don't remember the year of your heads, but IIRC, they were '70 heads. If so (or '69 heads), this would give your 302 bigger valves which will equate to at least some . performance gain.

... just some food for thought.
 
G

·
Guest
Joined
·
0 Posts
If I could take this advice myself, I would be very much happier -- Patience. Wait and save the $60 for head and intake gaskets for the build of your dream motor. The best scenario is having a second block that you buy your steel crank, etc for and build while you drive your old stocker around for fun.

Every time you see a bad a$$ car, it will motivate you to work harder on the dream motor.
 

·
Registered
Joined
·
3,897 Posts
Discussion Starter #6
Wow! Now I'm divided... ::

I agree that the 351W heads should be included as a performance "package" to fully utilize their potential. Then again, the actual "bolt-on" swap would be easy enough. Even though I'm leaning towards using the stock 302 heads for now...here's what I have:

Stock 302 which runs, (without checking the books, probably 9:1 compression or so, or even high 8's.) Stock cam, stock heads. Performance mods: Tri-y headers, 4v factory intake, and a Holley 600 vac secondary carb. Removed the auto trans, smog and regulatory stuff, and the 2v intake. A/C removed too. Horsepower gains will be realized just by the removal of the A/C compressor.

An option could be to "cam up" a bit and shave the 351W heads to up the compression back up.

The engine will be hooked up to a 3 spd manual tranny and an 8 inch stock rear with 2:80 ratio. Nothing fancy, just something that can be utilized on the street and highway. So I need a low end good torque response, not super high revving horsepower (though pedal to the metal might be fun once in a while!!). 351W heads may not be as usefull in this application? My idea is to have a little giddy-up and go with a basically stock engine, again, nothing too fancy.

Maybe this will help further the discussion along. Thanks for the input guys! :)

BTW, the engine has 80,000 original miles on it and ran great when it was parked. (The 81 T-bird got wrecked. Guy drove it off a "cliff" to avoid a head on collision!! ::) He was able to drive the car home though, the radiator wasn't even damaged, surprizingly.) So I'm doing the "gasket overhaul" route and am replacing the oil pump along with the oil pan in the process.
 

·
Registered
Joined
·
5,066 Posts
Last September I posted and ranted and debated with you all about the 351W heads water ports not matching the water ports on the older 302 engine block. Now, I have a nice little 1981 302 block and the block-to-head water ports match up perfectly. So I'm really tempted to mount those heads.

Question is this: Should I wait to use the 351W heads???

This is why:

1. The 302 runs. I am not going to rebuild the engine due to lack of funds at this time. I just want to detail it and get it in the car. All the support stuff to go with the engine, (clutch, batteries, drivelines, brakes, etc, etc, etc will cost aplenty anyway). So the thought being, get a basic engine in the car and rebuild a dream engine later.

2. If it were a matter of just installing the 351W heads and getting a performance upgrade instantly, I would do it. But a stock 302 has fairly low compression and the larger combustion chambers may lower compression further. I'm not sure I want to buy higher compression pistons (thus rebuild the block) or spend the $$ to shave the heads at this time. I would have to sacrifice buying something else that would help get the car going sooner.

3. Am not sure the 302 intake manifold would work with the 351W heads...

To buy new 1/2" head bolts, higher compression pistons, and the associated rebuild goodies, head re-work, intake manifold(?), would add up to a well over $1000 I don't have right now. Maybe I should wait, and not lose sight of the original engine goal.
you sound like youve already made your decision, bro ::
 

·
Registered
Joined
·
3,960 Posts
twotoots....

the place NOT to sacrifice costs is the powertrain....a deal is a deal...we all know that.....

Now onto the core of the problem.....get the heads milled to bring compression back up....check for valve clearances...
the adapting head bolts are about $100.

use the 351W style intake gaskets...the 302 intake will match up...

find out the stock cc of the low comp 302 heads....I think they were quite large....the right 351W heads have 60.4cc combustion chambers....so you may even see an increase...

I say go for it!!! You look like you're ready to bolt on them windsor heads!!

::
 
1 - 8 of 8 Posts
Top