[Stangboy5666]

How good are the 351W heads on a 302? The do bolt right up correct. I read in a book that they are very good street heads. (Im not talking racing) I wanna make my horsepower within the realm of reachable RPM's nothing crazy like 6000...right before my engine blows...

[Tominator]

I just bought a set of '75 351W heads on Ebay for $200 delivered. They are going on a '77 302.

Bad? Rail Rockers, but they are cheap. You need special washers to use the 7/16 head bolts as the 351 heads take 1/2 inch.

Good? About a point rise in compression over the '77 heads. Larger valves and better breathing.

Including head gaskets, I use the the better ones, and including new roller rockers I'll have less than $325 and gain about 25HP.

No bad HP for the dollar.

[mstngjoe]

Depends on the application and what heads you are running now.

In some cases you could loose compression and therefore power. For instance, on an early 289/302 that originally had 54cc chambers, you would lower the cr with the larger chambered heads. But if you've got some late model heads with larger chambers, you can gain compression, as stated above.

The swap was popular back in the day when cylinder head options were limited. Now it's almost cheaper just to go after market iron for a better head.

[Tominator]

Stangboy5666

If you can supply the casting number from the block and it has stock pistons we can determine the compression ratio. That is the key!

Tell me where you can find rebuilt aftermarket heads for anywhere near the price I gave?

I hear about Gt40 heads for $400 but in reality if rebuilt go for considerably more.

[mstngjoe]

Originally posted by Tominator

Tell me where you can find rebuilt aftermarket heads for anywhere near the price I gave?......

You can't. Are yours for sale?

If you've ever gone thru a set of heads the correct way with quality parts, you'd know what I was talking about. Good valves & seals, machining/installation of screw in studs, 3 angle valve job, fresh deck, decent springs, etc.

If you want a high performance iron head, it costs. If you want to throw on a set of stock heads that won't get you 10 hp, you can find them laying in any junkyard.

[Tominator]

There were three sets for sale when I bought mine...Screw in studs are NOT a neccesity and neither is a 3 angle valve job. Neither adds horsepower to a measurable degree.

A check of how flat the surface is which includes a resurfacing and a check of valve springs is exactly what I got.

I know what I have...you do not...

[mstngjoe]

Originally posted by Tominator
......I know what I have...you do not...

But I know what you don't have.

[Tominator]

I'd love to argue, but have rebuilt heads myself many times using long ago tools that would completely mystify you.

Ever run a flow bench? I have several large trophy's that will tell you I can build late 60s Ford small blocks....and a couple that will tell you I ain't bad with Mopar big blocks.

A long time ago to be sure, but given the original requirements, I'm confident my advice is sound.

[RobW]

Which cylinder head is "right" completely depends on the application. Anyone can argue this aspect over that, but the cam certainly has to come into play at some point in deciding which heads to use.

For a stock 302HO, I would consider 351W heads an upgrage, but only the pre 76 version for obvious reasons. But then, with a stock camshaft and intake system, I'd prefer ported stock heads because neither version has great inherent flow qualities anyway and with the stock heads you already have them and know they're a direct bolt on(allowing use of all factory equipment).

Overall, I choose aluminum heads for their extended values. That's my .02

[mstngjoe]

Not to prolong this, but for the sake of others who may drop by I'll point out a couple of things:

As mentioned above, a head change should take into consideration the cam profile.

I don't know of anyone who thinks screw in studs add horsepower of any kind in and of themselves. But they are considered a normal mod/feature on performance heads. The purpose of which is to allow a more aggressive cam profile and not pull out the crappy pressed in studs. A more aggressive cam makes more hp. The screw-ins will also let you dump the crappy rail rockers and move on to an adjustable valve train. Which is another pretty standard feature for performance.

Another component of performance oriented heads is a 3-angle valve job. Again, more hp.

If the reason for head change is an increase in performance, why do things half azzed. The heads you got for $200 are fine for a work rig or a grocery getter. You think those heads are worth 25hp? Post the before and after dyno sheets.

In the end, matching performance parts to achieve your desired power level is what's important. If you don't do that, you can never optimize your given setup.

[Tominator]

As you stated, it all depends on what you expect. My '77 F100 will be a daily driver and will never be expected to deliver the HP that my Ranger does.

I'll gain at the very least 25HP. I'm raising the compression by almost a full point and they have much bigger valves.

It will never see a dyno, but ask any engine builder that is familar with the swap and I'll asure you he will agree with me.

Btw, the 3 angle valve job is standard procedure and has been for years on any head rebuild.

The benefits or lack thereof have been argued about for several generations.

As with any proposed upgrades one must first state a budget. Then determine what your goals are. Only after those factors are addressed can one determine the modifications.

I just picked up copper header gaskets on Ebay for $15 delivered....He! He!

My F100 is getting about 50 HP on a budget that includes EFI, Mustang headers and the heads. Within my budget and the HP gain is secondary to drivability and fuel milage.

[mstngjoe]

Originally posted by Tominator
.....I'll gain at the very least 25HP. I'm raising the compression by almost a full point and they have much bigger valves.

It will never see a dyno, but ask any engine builder that is familar with the swap and I'll asure you he will agree with me.....

All other things being equal, a one point increase in compression ratio will result in approx 2%-4% increase in gross hp depending upon the engine. The increased valve size only gives a hp boost if you already had the correct cam/timing events that will take advantage of the minimal increase in flow. And then only in the upper rpm.

So yeah, if you're already making 500+ hp you might see a 25 hp gain from your $200 stock heads.

[Tominator]

So you are saying a larger valve area has no effect except in the upper rpm? True, the highest HP will be reached at peak rpm, but where is the argument?

Using your reasoning it would never be cost effective to EVER upgrade your heads

We are arguing for nothing.



The 75-76 351W heads have always been a great budget head swap on non-roller 302s.

Second in line are the Ranger GT40 heads and every 'upgrade' doubles the price.

[mstngjoe]

Fine.....

BTW Stangboy, sorry to highjack your thread.

[RobW]

Originally posted by Tominator
Second in line are the Ranger GT40 heads and every 'upgrade' doubles the price.

errrr

LOL Never knew that...

While I like GT40 iron heads, I'd never buy a set unless I intended to class race where they're required. For the couple hundred invested in 351W heads you'll do okay IMO. That said, it's well worth the price difference to get a good set of aluminum heads, for a 302.

The 351W head never really had a much larger valve than the 302 head and the fact, neither head flows worth squat, I don't see much gained. Of course, there is some gain, but it's not a whole bunch.

Side note: One of my brothers has a 302HO(factory bore/stroke) in his Ranger. It's got Edelbrock aluminum heads, TFS cam, intake, blah blah blah and a 125 shot of nitrous. Rans deep 11's on slicks. Not bad for a daily driver.