I am thinking about just getting my heads reworked when I start upgrading the engine, rather than buying alminum heads. I thought about the early 351 D0 heads, but if I have them ported and decked to bump my CR then what would be the advantage of the 351 heads over my 302 heads. I know the valves are a little bigger on the 351 heads but what size are they. I think I want to go with 1.94/1.60. It will be a street car that I want around 350hp. Thanks in advance...
Head Work (stock heads)
- Thread starter nugget68
- Start date
The old 289/302 heads with the large base spark plugs can only accommodate 1.90/1.60 valves. Newer heads will use smaller spark plugs and can accommodate 2.02 intake valves, but you lose the smaller quench chamber of the earlier heads. With proper porting, polishing and chamber sizing on the older large plug heads, you can get some pretty decent flow numbers. The heads will top out flow at just over .500 valve lift, but will also outflow larger valve heads when you add up total flow from .100 to .500 lift.
The total flow number will keep up high port velocity and mix rates making for a really strong, fast revving street engine (it will give strong signals to the carb). This is about 30% less cost than a comparable flowing new aftermarket head, and will make a strong engine.
Hope this helps, I will try and find some bench flow numbers from some heads that I had done a few years back.
The total flow number will keep up high port velocity and mix rates making for a really strong, fast revving street engine (it will give strong signals to the carb). This is about 30% less cost than a comparable flowing new aftermarket head, and will make a strong engine.
Hope this helps, I will try and find some bench flow numbers from some heads that I had done a few years back.
302 coupe
Founding Member
unless you own a machiune shop, aftermarket heads are cheaper and will yield better results. By the time you figure new valve seats, new guides, new valves and hardware, cutting and tapping for screw instuds, etc., you've already equalled the cost of an aftermarket head. If you pay somebody to port them, you'll go way over the cost, and still won't be making as much power.
67topless
Member
302 coupe said:
I can confirm this from experience. Wanted to keep my stock 289 heads, so I had them ported - micro polished - tapped and it cost a small fortune. At the time, I wanted to keep a much more stock appearance... that thought process has since faded into more of a resto-mod philosophy.
Get new heads
brianj5600
Active Member
I would also be careful about spending too much money on stock castings. If you plan on aftermarket heads down the road, I would not do more than a home port and valve job. Spending money twice sucks!
LMan
Founding Member
Good advice given here. You can get to 350 hp without much drama with the 351 heads, but port them yourself.
Anything more ambitious than that, go aftermarket.
Anything more ambitious than that, go aftermarket.
mj440
New Member
just get some nice world product cast iron heads for $500 and save your self the time and money and they will get you up to 350hp. plus it would be better than buying ported e7 for $500.00.
LMan
Founding Member
What's wrong with my avatar?
LMan
Founding Member
nugget68 said:
No, go to 1.94/1.6 Chebby valves. The rest depends on your combination, but yes, decently-done C9 or D00E heads can get you to 350 FWHP. For intricate details I will defer to Mr Hearne or other sage engine-builder types
..but if I was you, I'd get the Dart irons or something like that. The 351 idea makes sense if they are free or nearly so. I built a motor w 351 heads but I was all but given the heads for zip, so that made it attractive.
1320stang
Founding Member
You can get 350fwhp out of early 351w heads easily, I think I was getting about 450+ out of mine (11.0s @ high hundred teens with 5.67 gears, 9x30 slicks and 3000#, the Moroso Drag Calculator says about 400rwhp necessary). I think you can get 350 out of the stock 1.84/1.54 valves, I wouldn't use stock valves mind you, put some SS ones in it. You could do the pocket porting and bowl blending yourself. Personally, I think knowing what your heads flow on a street car is about the most worthless thing around. Race car? ok, but for a street car, it's nothing more than bragging rights. The only people that will care will be the people that don't know any better, people in the know won't care and are typically less impressed when you talk about such things. Maybe its because I'm damn near 40, I dunno. I'm typically more impressed with the guy that does more with less. It's been my experience that when most guys upgrade, they end up upgrading the heads as well, so I don't think the spending money twice argument holds that much water. My opinion is, if you haven't built an engine before, or done too much, build something that's mostly modified stock big parts, throw some aftermarket stuff in there like pistons & cam & induction. On the other hand, if you know what you want to end up with, why worry about upgrading, start at the end to begin with. The 289 I'll put back into my '65 will use the stock 289 block, crank, heads and rods and will likely make 325-350fwhp when done. I'll do some pocket porting on the heads as well as some bowl blending myself. The car should run some low 13's/high 12's on street tires when done. Now my FE for my Fairlane, I'm going to end up just about all aftermarket, Genesis block, Blue Thunder High Riser heads, Dove HR Tunnel Wedge, Pro Systems modified Holley 660 center squirter carbs, T&D rockers, Diamond Pistons, Scat 4.25" stroker crank, 6.7" rods, not sure what cam, but it'll be solid roller. But initially I'll be building a stroked 390 with iron heads making about 400-450fwhp to put into the car to sort of break the car in and get me used to it. Then the plan is to pull that engine and throw it into a '67 coupe, primered black, with a home built C6, throw 150 shot on it and have a little play toy. The good engine will then go into the Fairlane and hopefully make in the 650-700fwhp range, the car will be built legal to 8.50's.
If you really want low buck, get a good used, low mileage set of E7's, hog out the exhausts, removing the thermactor bumps, widening the sides to match the gasket, raise the roof as well. Blend this down into the bowls. Blend the intake bowls too, just leave the ports and passages as is, only remove any sharp edges. Ditto on the chambers. A good low mile set will likely just need a valve job afterwards ( preferably with a Serdi Machine to contour the seats) I did this with a couple sets, only had maybe $200 in each when done. The results I figure should equal the iron GT40 heads.
Similar threads
- Poll
