I've been searching through old threads till my eye's are blurry. I've seen alot of people using 379 heads on 348's with good results, even on stroker 348's. I haven't been able to find any threads on 791 heads. In the head casting numbers section on this website it doesn't say much about the difference between 791 and 379 heads except water passages were added. My question is, How comparable are the 791 heads to the 379 heads (port shape, port size, ect) ? Any input would be greatly appreciated, Thanks, Heath
question about heads
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Just a suggestion...
Heath:
Just a suggestion, but I suspect you can get a set of 333 heads for about the same price as a set of 379s, and my understanding is that you will have a better base from which to work. Someone will correct me if I'm wrong.
Good luck!
TomK
Heath:
Just a suggestion, but I suspect you can get a set of 333 heads for about the same price as a set of 379s, and my understanding is that you will have a better base from which to work. Someone will correct me if I'm wrong.
Good luck!
TomK
Thanks for looking. I've been wanting a W for years and have gave up on a 409. I finally found a 348. It already has the 791 heads. I was looking at the head description on this website and they descibed the 147 heads as identical to the 379 heads with bigger valves. I saw a bunch of threads here where people had good results with 379 heads, and if the ports were unchanged from 791 to 379 heads...well. :? So unless I find some big port heads really cheap I may just stick with what I got
Please, any more input would be welcome. I may end up stroking it, but a really only want about 350-400 hp. Something to make a daily driver gasser out of, but enough hp to make it respectable and fun to drive. It said in the casting numbers page that those heads came on 250/280/315 hp engines, so I don't think 400 is unrealistic with these heads.
Anybody...
Please, any more input would be welcome. I may end up stroking it, but a really only want about 350-400 hp. Something to make a daily driver gasser out of, but enough hp to make it respectable and fun to drive. It said in the casting numbers page that those heads came on 250/280/315 hp engines, so I don't think 400 is unrealistic with these heads.
Anybody...
Better heads
I think you can pick up 333 heads for $50 to $100 bucks a pair, and if you put big valves in them, they will be better than 379 or 791 heads can ever be. I think I stated this in an earlier post, but there is not enough port wall thickness in a 379 head to make them as good as an unported 333. Hell, #817 340 hp 409 heads are going for about $300 a pair.
These bigger runner heads heads will allow you to make more power while requiring less cam duration.
I think you can pick up 333 heads for $50 to $100 bucks a pair, and if you put big valves in them, they will be better than 379 or 791 heads can ever be. I think I stated this in an earlier post, but there is not enough port wall thickness in a 379 head to make them as good as an unported 333. Hell, #817 340 hp 409 heads are going for about $300 a pair.
These bigger runner heads heads will allow you to make more power while requiring less cam duration.
Some suggestions
One way to beef that 348 up would be to slip a 409 crank in there, it fits with no grinding required. You might look into a new set of BBC rods, and you'll need to measure for pistons to make sure you have the right combination. I think with some inexpensive 333 heads, bigger valves and strong springs, and a good cam, you should be able to get near 400 horses. Depends on intake and carb as well...
Lots of possible combinations that you might consider. look at some of the previous threads to see what others have accomplished.
Good luck!
TomK
One way to beef that 348 up would be to slip a 409 crank in there, it fits with no grinding required. You might look into a new set of BBC rods, and you'll need to measure for pistons to make sure you have the right combination. I think with some inexpensive 333 heads, bigger valves and strong springs, and a good cam, you should be able to get near 400 horses. Depends on intake and carb as well...
Lots of possible combinations that you might consider. look at some of the previous threads to see what others have accomplished.
Good luck!
TomK
I like the 409 crank option (depending what a 409 crank sells for) because of the money you save in machining a 396/427 or 454 crank. The only 409 crank I've seen was on ebay for $650. I also saw a NEW 4" (454) crank (maybe scat, can't recall) already machined for a W for the same price. Hmmmm !
What do you mean by measure the pistons...
Thanks, Heath
You can probably find a 409 crank for 300-350 easy. I have several. You can get a new Scat for 600-700. Just order pistons for your stroke and rod combo.Region Rat
the 333 and the 817 are both "small port" 409 heads.
Cool. couple questions.
With a 409 crank, I can use my 348 rods? What about a scat crank are the rod journals the same on those of the 348? And are the 348 rods decent rods? I only ask this because their longer, and longer rods cause less stress on the cylinder walls. ( I can look these numbers up later if nobody knows it in their head)
How much better can the the 333 and 817 heads be if they have the same ports? Were they different shaped ports, different plug location, ect.
Thanks
I do see tht build it said they have bigger ports and more port wall thickness. Even though they are small port heads, they are bigger than the 719 ports?
With a 409 crank, I can use my 348 rods? What about a scat crank are the rod journals the same on those of the 348? And are the 348 rods decent rods? I only ask this because their longer, and longer rods cause less stress on the cylinder walls. ( I can look these numbers up later if nobody knows it in their head)
How much better can the the 333 and 817 heads be if they have the same ports? Were they different shaped ports, different plug location, ect.
Thanks
I do see tht build it said they have bigger ports and more port wall thickness. Even though they are small port heads, they are bigger than the 719 ports?
rods
Ditch your stock rods no matter if you use a 409 crank or not. Unless you are just building an easy driven [ if that is even possible] W motor. Todays rods are much better metallurgy wise and considering the cost of rebuilding your stock rods and replacing rod bolts, you will probably be saving money with new ones. Then you can have a 6.135 rod too!
Ditch your stock rods no matter if you use a 409 crank or not. Unless you are just building an easy driven [ if that is even possible] W motor. Todays rods are much better metallurgy wise and considering the cost of rebuilding your stock rods and replacing rod bolts, you will probably be saving money with new ones. Then you can have a 6.135 rod too!
Cost comparisons
The "333" heads are from truck engine builds, serving both the 348 and the 409 from around 1963 on (I might be off a little on that date). They are plentiful and after Lamar Walden labelled them as "door stops" in a presentation made in 2004, they haven't commanded much in terms of price. In terms of value, they are a good deal for the price. Similar in design, but more expensive are the "817" heads, which came on the detuned 340 horse builds of 1963-65. These will run you more like $750 a pair, as their perceived value is higher. The "1147s" are from the earlier hi performance 348s, circa 1959-60-61. These are also in high demand, even though they don't offer that much more in terms of performance. A good set of these can run you up to $1000. Since they are all about the same, the best value is in getting a good set of the more plentiful 333 heads, match the ports to the intake and gaskets, install some bigger valves and stronger springs to match your cam, and you'll have a pretty inexpensive top end.
You've indicated that you want to develop some power in your build, Used rods are not the place to save dollars. Save them on your heads. Buy new rods and pistons. That's my recommendation, but you can do what ever you want!
Good luck,
TomK
The "333" heads are from truck engine builds, serving both the 348 and the 409 from around 1963 on (I might be off a little on that date). They are plentiful and after Lamar Walden labelled them as "door stops" in a presentation made in 2004, they haven't commanded much in terms of price. In terms of value, they are a good deal for the price. Similar in design, but more expensive are the "817" heads, which came on the detuned 340 horse builds of 1963-65. These will run you more like $750 a pair, as their perceived value is higher. The "1147s" are from the earlier hi performance 348s, circa 1959-60-61. These are also in high demand, even though they don't offer that much more in terms of performance. A good set of these can run you up to $1000. Since they are all about the same, the best value is in getting a good set of the more plentiful 333 heads, match the ports to the intake and gaskets, install some bigger valves and stronger springs to match your cam, and you'll have a pretty inexpensive top end.
You've indicated that you want to develop some power in your build, Used rods are not the place to save dollars. Save them on your heads. Buy new rods and pistons. That's my recommendation, but you can do what ever you want!
Good luck,
TomK
just worth mentioning but awhile back Ronnie mentioned that it wasn't much difference in cost to just go with the Edelbrock heads versus doing a bunch of work to a set of 333s once your figure in freshening them, new springs, new valves, port work, etc 
Always a tough decision. I have $1,250 in the 333s. Add 30 hrs of labor for the port and bowl work. Flowed 260 cfm. Very happy with that but I can't say what it would actually cost to reproduce them. If you would have to pay for the port and bowl work,, then the Edelbrocks would be the way to go. Even basic machine work to put 333s into shape can run into big money. Yesterday, fired the " low budget" motor. Project changed. In the first place it is not low budget and Brian Thompson now owns the engine. Not sure of its future but I think Brian may have to sell it. Not a very exciting video but it was nice to get through cam break-in and hear it sing a sweet song.
Watch the CR if you use 333 heads. you will need about a 1/2 point bump in the pistons to make up for the small camber in the heads.
10:1 with 817 heads would be about 9.5 with 333 heads
Ronnie Russel got some really good numbers from 333 heads.
If you want 348 rods, you could at least use BBC rods. The diffences is like a 283 rod to a 350. You also would need to balance for the BBC rods and new lighter pistons.
10:1 with 817 heads would be about 9.5 with 333 heads
Ronnie Russel got some really good numbers from 333 heads.
If you want 348 rods, you could at least use BBC rods. The diffences is like a 283 rod to a 350. You also would need to balance for the BBC rods and new lighter pistons.
Thanks everyone, that was a BIG help.
One more question.
Do Edelbrock heads 333, 817, 1147 heads all share the same intake ?
I saw the later heads used a different intake from the earlier heads. If I found a good deal on a 2x4 or crossram intake(
) like that'll happen, would it work on all of these heads or only the later large port heads ?
One more question.
Do Edelbrock heads 333, 817, 1147 heads all share the same intake ?
I saw the later heads used a different intake from the earlier heads. If I found a good deal on a 2x4 or crossram intake(
) like that'll happen, would it work on all of these heads or only the later large port heads ?
unworthy, The Edelbrock head and the #690s and the #583s require the large port intake. The others require the small port intake. Edelbrock offers both intake designs in both single 4 and 2x4s. Oops, after thinking about it , I am not sure if Eddy offers the single 4 for the large port heads. Would have to check on that.
I don't think you mentioned what version of the 348 block you have. If it came with 791 heads, then I assume it's a 58, but which version? If its an 811, or an early 872, then it doesn't have spark plug cooling and you would have to plug the cooling ports on any 379 or later version of head you use.