Hi Everyone - I'm new here and this is my first post. I have a 70 GS350 that currently has a Demon carburetor and a Poston intake with a 1" spacer that were installed by the previous owner. Right now the car runs great but I'm looking to use the original ram air intake that I have, however it will not work with the current set up. I'd like to lose the Demon and switch to a Quadrajet and have reached out to Quadrajet Power, about having one built. My question is, is anyone here running a Quadrajet with a Poston intake and if so how is this combination working out and is a spacer being used? I've read a lot of negative things about this intake but I've also heard a spacer helps but I concerns about hood clearance with the GS intake and a spacer. Also, am I correct that the 350 has a little extra hood clearance? I figured this since the 350 foam seals for the intake are taller than the 455 ones. If so maybe a small spacer could be used if necessary? Any input would be much appreciated! Thanks in advance, Jason
If it runs great, I'd leave it alone. Save your $ and keep the Demon. You won't have any substantial airflow gains with the factory cleaner & snorkels anyway.
First, welcome! Post some pics/details of the car. I assume you want the QJ/air cleaner for a more stock looking setup. I don't know for sure on the Poston intake, but I ran a QJ/spacer (1" IIRC) on a TA intake & the the stock air cleaner was ok. You're correct on the 350 having more hood clearance than a 455. About an inch diff. in the foams (maybe a little more). If you get a carb, I'd get one that was orig. for the car (7040244) or something close - I think I just saw one for sale somewhere too. May have been on CL. Might want to talk to @Rob Ross on here too (you can message him directly from his profile page). He builds a good carb.
Everything I have ever read about the Poston intake say it wants a spacer to run it's best. Not sure about the Poston carburetor pad, but if it is more centrally located to equalize the runner length, the GS Air cleaner will be too far forward by a few inches. If that is the case, you'll need a stock intake or the TA 350 intake, http://taperformance.com/proddetail.asp?prod=TA_1235 Both the TA intake and Poston intake are drilled for both spread bore and square bore carburetors. The stock intake needs an adapter to run your Demon square bore carburetor. With the TA or Poston intakes, if you use a braided carburetor line, you can configure it to run both the Quadrajet and Demon carburetors, and easily swap them in 15 minutes or less as I do.
I've got a TA Stage 1 350 intake and it works just fine with the factory breather but it no longer rests on the breather support that bolts to the thermostat housing studs.
i machine the poston's to fit a supercharger on it. forced air really doesnt care how it gets there. if you cut the postons open, you will say 'how the hell does that work?' really wierd paths. don't know why carbs work on it.
Thanks for the information! Yeah I'm not looking for any performance increase, just the ability to use the GS intake that I have for a more stock appearance. Looks like I'll give the Poston a try with the Quadrajet and spacer and see how it works.
I would just work with the Poston intake. They work just fine especially with a spacer. I have a Poston intake on my 455 and my wife's 350. Both are running a 3/4" spacer. I tried all kinds of spacers on my 455. Open, semi open, semi divided, and 4 hole. My 455 runs best with a 4 hole square cut bottom. I am running a 4 hole with tapered bottom on the 350 and it performs impressively. That engine is a solid lifter cam with ported heads. I run quadrajets on both engines but I would probably leave the Demon on your engine and try to make that setup fit with the air cleaner and whatnot first. If you do swap in a Quadrajet I would say try a 4 hole like what I have posted here. It is Mr. Gasket. It is much like what I have on my engine. Greg
Thanks for the info Greg I appreciate it! I get leaving it alone and using the Demon but the air cleaner I have is in great original condition and I'd hate to mess with it to make it work. Plus I have been wanting to switch to a Quadrajet for a while anyway.
I ran a 750 Holley with a TA dual plane, 1" spacer, and used the GS air cleaner. Just don't use the front support bracket and let the snorkles flex down some...
