View Full Version : Head Question!!!
Ok, I am likely going to move in July, not too far. I do not want to tow my mav to the new place, gonna keep it dignified. Over the next few weeks I am going to pull the gas tank and clean out the blockage and...
I had the heads rebuilt a few years back by a buddy in an auto shop class. Ever since bolting them on I have had partial compression on the second to last one on the drivers side, and little compression at all on the last one same side. So basically the car runs on 6 1/2. I am going to stick another pair of heads on the car so here is my question my question.
I want to buy decent used low milage heads and put them on. I can get 87-93 5.0 heads CHEAP. To the best of my knowledge, these are a direct bolt on. Will this increase/rob my power. I know in 72 the 302 lost 1/2 point of compression, going down to 8 1/2 to 1. will these bring it back up to 9 or? So taking for granted they are a direct bolt on, what has to be changed? Will the stock exhaust/intake manifolds bolt on? I am choosing these heads for sake of how easy they are to come by in good condit. What are everyones opinion about swapping on 351 Windsor heads. I heard 69 was the best year, what about the newer gen 351's? Anyway, doing this on a budget, obviously, and I thought I would see what every one else thinks before I get started. Looking for the least amount of work/ and most gain. I will also be putting on a new edelbrock manifold I will buy with a 4 bbl holley I already have.
The 5L heads have a different rocker arm assembly and you need to use the right length longer push rods due to the longer 5L roller lifter. I don't think there will be any compression gain. The intake and exhaust will bolt on ok. The early 351 head would be the best selection besides an after market set. They should have hard intake and exhaust seats installed for long life. Any way you go, its going to cost a little to do it right.
351W heads from 1969 to early 1977 are identical in:
Valve size: 1.84"/1.54"
Combustion chamber size: 60.4 cc
The only real difference is 75 up have internal air injection plumbing.
During the 77 model year, the heads got monster chambers, small valves, and small ports. They became identical to 302 heads that year. The only difference between 302 and 351 heads after that was the head bolt holes. Also all SBF heads went pedastal rocker with this design.
There are folks that believe the 4V heads or the early heads or certain casting # heads are best... but the fact is, as described above, they are all the same for 351Ws.
The wide difference in compression ratios was handled by a variety of piston configurations, not cylinder head changes.
So, IMO 1974 will be the best year 351W head made. It will have all the above attributes plus is pretty sure to have hardened valve seats and would be dirt cheap as any seller would be convinced they are NOT a casting of any good caliber.
My mind is made up. I am going to scout around for some 351 heads. There are no modifications at all that need to be done to accept the 351 heads?
The bolt holes on 351w heads are larger than on 302s because the head bolts are larger. It's not a big deal, you just need a shim kit or large shank bolt kit for the swap to maintain good alignment of the head on the block. Over the years the water passage on the intake face of the different engines has gone through slight changes, so you might have to sort through some intake gasket sets until you find a set that is a good (read sealing) compromise between intake water passage and head water passage. They pretty much all seal... unless one of the surfaces has major corrosion.
i just happened to be at the ford dealer today and asked about the head bolts for the 351w to 302 head conversion. the part number for the bolts is M-6065-D289. they would have to order them from another dealer and couldn't tell me the price. if i remember right they were a lot cheaper than the ARP bolts, but i would consider what i was going to use them for. if you are going to race at all, i would consider an aftermarket set of heads. there are many good ones for the sbf now and the cost is cheap compared to what you have to have done to the 351's to make them competitive. not trying to stop you from using the 351's if you can get them cheap enough and are strictly going for the street. i have 351 heads on my 351 maverick, but i put about $800 of work into them. i think now that i'd of been happier with an aftermarket set, but i've got too much into them now (next time maybe). if you find some, the c9's (69) or d0's (70) are supposed to be the best from everything i've read. i'd like to know what there worth these days if you find any. good luck.
I'm sure it was a deal...I paid $75 for a set of D0 (1970)
351W heads. I went to www.fastvalves.com and bought the pro-flo style 1.94/1.60 stainless valves, ARP studs and retainers for around $225. My machine shop guy cleaned the bare castings, magged and machined them for the above parts, (cut the bowls etc.) milled them and got everything right for $375. So, I have $675 in them. I probably could have gotten a set of Edelbrock
Performers for around $950 or so at a show where I didn't have to pay for shipping.
I'm hardheaded. I probably should have gone with the aftermarket heads, but I went with the 351's anyway.
(this was in the past 6 months)
I would not put the 351W heads on an otherwise stock motor. The larger port volume of the decrease low end torque. JMO.
really? that is a good point. Has anybody experienced this, how much loss? I just emailed a guy about some heads, but I low low end torque probably more than high end power. Upgrading to a bigger intake/carb might help? I already have a good dual exhaust setup
I first purchased a set of 63' 289 heads and replaced the valves with Manley Race Flo valves and had them ported and blended and a 3 andgle valve job and screw in studs and so on and so forth.....to make a long story short I had $1200 total in the heads....and man they did great but you need to remember that those heads are 1963 technology no matter how much you port them THEY ARE STILL 1963 TECHNOLOGY.....I think some people refer to this as "POLISHING A TURD"....... well later I purchased a set of aluminum heads for a similar price that out of the box made the 289 heads feel like good candidates for boat anchors....the old cast iron heads are good for Nostalgia racing and classes that require old style heads but other then that they are not what you want for a "PERFORMANCE" application.....
I agree with him. Especially if you are talking about bolting these heads to a stock short block(factory pistons etc.)
Mine was built to give 10.5:1 compression with Keith Black pistons and a milled and squared block. The heads were milled as well to yield the proper compression.
It is still not a race application as I used a milder cam, I just wanted to see what I could do with the 351W heads. If I did not know a good machinist who would treat me right, I would have bought the Edelbrock heads.
Thats what I suggest that most people should do anyway.
I'm becoming my Dad! Do as I say, not as I do!
Alright, I have been talked out of it. A few years back I rebuilt some 68 302 cylinder heads at auto shop for the hell of it. I put in all new exhaust/intake valves, knurled the valve guides, and grinded the seats all with a 3 angle valve job. I will dig them out of storage and put those on. Anyone need the old heads that I am going to pull off? I think I had new intake valves in them a couple of years back, and ran it only a few miles since then.