I have a new edelbrock 500 (4 barrel spreadbore) carbie that I want to turn quarter of a turn on the manifold. The manifold doesn't have enough meat on the surface where the carbie mounts to just redrill more holes. Is there an standard adapter available for this purpose, or does anyone know a simple way of doing this! I'm intending to use a phenolic spacer, as heat will be a issue. I have approximately 25 - 35mm height clearance to play with. It's an alloy manifold. I haven't got any knowledge (I've never seen it)of phenolic but was wondering if I can drill and tap it. If so will it be strong, and stay flat! If so then I could bolt this on first and then put studs in it to bolt the carbie on, or do I need to make up an alloy plate first, and then add the phenolic spacer! cheers
sifty,
Feb 17, 8:43am
I would search US websites, chances are there is something available somewhere. Or any decent machine shop could make something up I'm sure. Are you turning it for clearance for something! Is there another option!
quickstitch,
Feb 17, 9:38am
assuming that the holes don't overlap each other when rotated then get a bit of 1" alloy lazer cut to suit. countersink the machine bolts that will bolt the adaptor to the manifold, and have the holes drilled and threaded for the carb studs.
pdc1,
Feb 17, 12:45pm
Pretty much what I intend to do. Wondering if I can do this with a phenolic spacer instead of the alloy. I have not seen phenolic yet and weren't sure of the properties, whether is a strong stiff plastic, that will drill and tap ok etc, or whether it is brittle/too soft etc, and is just suitable as a sandwich. Just checking that there isn't an easier option, such as ordering an adapter off the shelf. It maybe that I build a temperary one out of ply or hardwood first just to try things out. It's on a straight six that will spend most of it's time running on the primaries. This means that the primaries are located forward of centre and make the intakes for different cylinders all different lengths. I was thinking if I turn it quarter of a turn the primaries are on the outside perfectly centre on the engine. It also make the intakes all of a very similiar length to each cylinder, therefore I would expect a much smoother power in low speed running and maybe more torque! Just wanting to try out the theory without spending too much.
pdc1,
Feb 18, 7:49am
Thanks, I realise that I may not notice any results. Just wanted to try and see, and as you said all part of the learning. It's on a manifold made for 4 barrell and it's currently setup and running with the edelbrock on it and runs well. No problem in size. I 'm having a little trouble in hot starts after being run hard and turned off for a few minutes, and I think what is happening is the fuel is boiling in the carb -well it sounds like it. Therefore I need to pull the carb to put a heat stop spacer in it anyway. Putting a single carb on an inline six is never going to work as far as equal lengths go. I was just trying to make the best of what I have. Having the two primaries to the front in effect adds (guess) 50mm length to No 6 and shortens No 3 & 4 approx 50 mm. Turning it to the outside means that 1 and 6 intakes are exactly the same and now 3&4 are at their maximum length. I don't know how much difference it all makes, as the engine already runs very well, just wanting to try and see. I think I'll just get a piece of wood or something and give it a go.
quickstitch,
Feb 18, 9:09am
if your intake is above the exhaust like xacoon's then a heat shield will deflect alot of heat, and a phenolic spacer will stop heat soak but you will still get some radiant heat while car is sitting dormant. a hole in the bonnet will help dissipate heat quicker,alsotry a fuel cool can.
quickstitch,
Feb 18, 9:25am
and HPC coat your headers, or exhaust wrap them.
xacoon,
Feb 18, 9:49am
gotta say the only time I have ever had problems with boiling fuel with an edelbrock was when the fuel line was getting heat off the manifold, rerouted line and it was sweet. on the pre crossflow I just made a point of keeping the fuel line away from anything warm and have never had a problem, its a heated manifold too, and its not as if I nanny drive it.
elect70,
Feb 18, 1:49pm
could always go whole hog make a"bath tub type manifold , put 2 X2 bbl carbs onspaced apart,The pro stock boys do it ( but its actually a single 4 BBl cut in halfas only allowed single carb , bit OTT for an amature tho )
pdc1,
Feb 18, 6:03pm
Thanks coon, exactly what I want to do -however different motor. It seems to make the most sense to me. Why the manifold manufacturer - aussie speed, didn't allow the carb to be this way amazes me. I had wondered about getting the manifold built up with weld, but was a little concern about distorting it. I definitely don't want problems with air leaks. My fuel line is steel which is no doubt most of the problem. It only does it when it is shut down quick after a hard run. I'm getting my extractors HPC so this should help, and I'll change the fuel line. p.s. did you every run the falcon with the carbie the other way, and if you did was there a noticable difference, and do you do high speed cornering! I was wondering what may happen to the float/ fuel levels in corners!
pdc1,
Feb 18, 7:47pm
In hind sight I probably should have. I did think about it. I liked the idea of the edelbrock with the small primaries, and I didn't have to worry about linkages and balancing them etc. Also some of the 2 barrels that I considered using would have meant there was 4 barrels open all the time with 2 carbs. The eddy are quite economic on fuel. I haven't pulled one apart yet but think they lean the fuel mix under high vacuum! The manifold I'm using has a divider in it to lengthen the middle cylinders, so it isn't that bad for intake length variations.
xacoon,
May 3, 8:51pm
never bothered running the carb the other way, half the reason I got this manifold is so I could run it this way. its a daily driver but it does get driven hard, fair bit of fast cornering yeh. these motors come out with a stromberg on and I wanted to go with a weber, so building up with weld and re tapping is what I did. never caused any problems, made it look factory actually, and it meant I could fit it under the bonet, not much room to play with in the xas and I could only just fit an air cleaner on as it was. with this edelbrock I have had to go with a low profile carb hat to get clearance.
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