Howdy, I have a stock intake on my 1956 265 SBC. I purchased a polished typhoon manifold to replace it with. Some people say there is a slight difference between the 55 and 56 manifolds and the 57 and later. Is there any truth to this?
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Howdy, I have a stock intake on my 1956 265 SBC. I purchased a polished typhoon manifold to replace it with. Some people say there is a slight difference between the 55 and 56 manifolds and the 57 and later. Is there any truth to this?
Not that I am aware of in terms of interchangeability.
Thanks what I think too. They mentioned oil leaks.
I also bought a Street Demon carb with the polymer fuel bowl to go with it. And a new set of ceramic coated headers to replace my tarnished stainless ones.
Your on the move should be a good mod.
A 265? I think you may be a bit over on the carb/intake. Is the setup for strip or is this a driver?
I think Scooting's right. The Street Demon only comes in two sizes, 625cfm and 750cfm, and I'd think both are going to be too much flow volume for your 265. Maybe something like Edelbrock's 500cfm Performer might be a better fit? Got that from an on-line cfm calculator - http://www.gtsparkplugs.com/CarbCFMCalc.htmlQuote:
Originally Posted by Scooting
Agree with over the top on the intake manifold. That design (same as Performer RPM) was first used on a 302 Chevy that used a mechanical flat tappet cam and could easily rev to 7000 or more. I think it is way too big for a 265 streeter and will result in a soggy bottom end due to insufficient mixture velocity. I wouldn't be concerned as much about the carb. Its vacuum-operated secondaries will only open as far as they need to based on demand from intake manifold vacuum. As long as the primary bores and venturi size are not out of proportion to any other 4-bbl, you should be ok. At street revs, you may not ever get into the secondaries with your limited 265 cubic inches.Quote:
Originally Posted by Scooting
I would offer that driveability would be far better with a stock manifold from a 70's or 80's 350.
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If it's an older Street Demon, it could be a 525 cfm, I've got one on my 302 (347) and it works well.
Tom, not trying to be critical of your approach. You may be more interested in the appearance of the new parts & pieces, and not looking for improved/ultimate performance. You're definitely making changes to dress up the old truck, for sure! It would be great if you have time to post some pictures of the project, before & after?
I am more concerned with looks and sound than perfomance. The demon is a 625 cfm. I have a pretty radical cam in it and it's been bored and had some head work done. I've been driving it for a couple years and have never had the secondaries kicked in or had it on the highway. I just cruise my neighborhood and local car meets.. We will see what happens. I'll see if I can post before pics. These are going to be big.
do whatever cranks your boat .. many folks have put wrong combinations together and learned to live with them ...
Are you running a road draft tube? The valve covers appear to have the mounting bolts straight across, if so the heads are not stock 265's. All 265's and 283's from 55 to 57 had staggered mounts on the valve covers and they also have no motor mounts on the side, that changed in 58. You won;t be over carbed if you have a fairly stout cam as I ran a 30-30 in a very bored out 55 265 block and it ran the 2-4 setup from a Vette along with a Sheiffer 10lb aluminum flywheel and it would easily grab 7 grand and then some if I kept my foot in it.
I am running a road draft tube and the heads are stagger bolt. We will see how it works if there are problems I will go another route.
Is there a small triangle cast into the pads at the bottom end of the heads? If so they are power pack heads. As far as changing the intake you shouldn't have any problems except for sealing the ends and I would use RTV instead of the supplied gaskets.
RTV for sure.
You will need to re-jet that Demon and change out the squirters so it won't run so rich. I would hold on to your present carb. You may wish to re-use it if you cannot tune that Demon. A lot of guys have had problems trying to dial them in. How about posting a photo of the entire car. You have me curious to see the rest of it.
heres a current pic Rumrumm. I'm in the process of putting a black canvas top on it too. Plus dropping it an inch all around.
Nice! Sometimes a soggy bottom end does not matter quite so much with a light weight car. You'll just have to experiment and see if you like the results.
Thanks, I'll post the results after I install it.
Wouldn't the dual quad wcfb's they ran in 56/57 flow as much fuel as a 625 cfm demon? Especially if the demon is detuned?
The WCFB's ranged generally from 375 to 500 scfm, and there were something like 222 different models built through the years they were made. To your question, yes, a pair will flow more than the Demon, and maybe as much as 1000 scfm. A good link - THE CARBURETOR SHOP /Carter 4 barrel carburetors
NTFD, my heads are the lower compression heads without the triangle on the rectangle. I'm looking at some of the power pack heads 3731539. These were used on the '57 283-283 hp engines. Will these work on my 265 with stock pistons ya think?
Thanks,
Tom
Tom I like the look of your truck. I'm also curious of the maker of your fan shroud. I need to get one soon for my truck, and lack the tools to fabricate one.
Thanks Steve. I made the shroud from some sheet metal from home depot. I had to make it in two pieces to be able to install it with the fan in place. It is pretty crude but seems to do the job.
Nice looking truck!
".....Wouldn't the dual quad wcfb's they ran in 56/57 flow as much fuel as a 625 cfm demon?...."
While a pair of WCFBs will potentially flow as much or more than the Demon, as the link Roger posted says, most have have a secondary air valve that effectively prevents the secondary from operating until sufficient vacume is created to open them.
"......I'm looking at some of the power pack heads 3731539. These were used on the '57 283-283 hp engines. Will these work on my 265 with stock pistons ya think?....."
Depending on the source book you read, those heads are 59 or 60CC chambers and if your running stock compression (8.5) with the low performance heads they should move you up to a bit over 9:1-9,25:1. There were several other casting numbers used on the PP heads (the ones with the pyramid) over the years, but the later ones would have the valve cover bolt holes that are straight across.
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If I remember correctly, the 283 I had in my '59 Impala had the lower compression head that came with the 2 bbl carburetor which was 8.5:1 compression. By swapping to a power pack head, it raised the compression to 9.5:1. Feel free to correct me if my memory of an event 47 years ago is incorrect.
Thanks for the info. Incidentally, the Typhoon intake is a no-go. There is no way to seal the larger runners to the heads. I'm going to smooth the stock manifold and have it chromed or ceramic coated.
The power pack heads from 57 and the engines they were used on were rated at 265/270 hp, I don't remember which, and the 283 hp heads came off fuelie engines and are rare as hens teeth. To retain the valve covers you have you will have to find heads from 57 or earlier. If your engine is stone stock it will be running a solid lifter cam. At one time I ran the fuelie cam from 63 in my coupe and the valve lash was 8 on the intake and 12 on the exhaust and it would spin higher than 7 grand as I bent some push rods one night in Oceanside when I'd had one too many.
NTFDay, I think the rare fuelie heads are the 997 heads. The charts I see show them as heads for F.I. and 4 barrel and hp from 220-270. The chart shows the 283 hp heads to be the 539 casting. This could be wrong maybe.
Don't know about casting numbers, but from what I remember about the 57 fuelie heads is that they had two rectangles on top of the pad, one short, one long. I do remember that 283 hp was first offered in 57 with FI and GM made a big deal of it, 1 hp per cubic inch.Quote:
Originally Posted by TomJ
This is the cam card for the Isky 30/30 I have in the garage
Tom how did you cut the nice radius in the sheet metal? If it doesn't require special tools I'd be interested in doing it myself.
Steve, tinsnips, I have a little 3 foot sheet metal bender I bent the sheet with. you could probably rig something with angle irons to to that.
NTF, I think the reason those fuelie heads are so expensive is that they are rare. I doubt they are any different thant the 283 hp heads. I have like an 097 cam in it now that is like the original Duntov cam. That 30/30 cam is little to hairy for me.
Offenhauser 360 SBC Intake | eBay
This would work fine for your application and IMHO it's hard to beat an Offy 360º. I'm convinced it's the manifold Chevy copied and used on the 67 Z28.
Thanks Tom!
NTF, do you know what the port size is on the offy 360? I bid on one on ebay then got to thinking the ports may be too big for my heads same as the typhoon.
I sure do like that gauge set up, wish you luck on your man/carb change.
I'm not sure and I can't get to the one I have in the garage, but suffice it to say that the only thing that will fit your heads exactly are heads from the era. I doubt that the exhaust ports line up exactly with your headers either. I wouldn't worry too much about the ports lining up since it won't make that much difference with what you expect of the engine. There is only so much that can be designed into a mass produced intake manifold and IMHO Offenhauser came upon the optimum design in the 360º years ago and everyone else has been copying since. I wouldn't think twice about dropping one on your heads with no more than a Holley 600 with no more than 62 jets in the primary, probably smaller, and no more than 64's in the secondary.Quote:
Originally Posted by TomJ