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Daveputt · 06-09-2014, 06:48 PM

Quote:

Originally Posted by Daveinet

Stomp on the gas... , Actually the biggest difference is in the heads. Each of those 502s have different heads. The HT has peanut port (round) heads. The HO has huge rectangular port heads. The ZZ has smaller oval port heads. It may be hard to tell the difference between the HT and the ZZ because one is round and the other is oval, however the HT is 338 HP stock, and the ZZ is 502 HP stock. So if you hold full throttle up to redline (5200 rpm), where does the power start to taper off? Does the engine seem to continue to increase power all the way out, or does it tend to roll off after 4200 RPM? Also the ZZ 502 had a factory aluminum intake, where the HT reuses the 454 intake, which is probably dual plain, unless it was replaced.

Also if that is the stock air cleaner, get rid of it. It can not flow enough air for any of those engines. I tried the stock air cleaner and it runs out of air above 4 grand. Really falls on its face. Huge difference between the the stock filter and my current setup above 4 grand. Below that is not much different, although I loose a little off the line.

I am always impressed how much you guys know on this thread. Going to put the air cleaner on my list of upgrades. Any preference on type and where to buy?

spritz · 06-10-2014, 07:08 AM

Just got back from a short vacation. GLAD to see you got her home.

Daveinet · 06-10-2014, 11:19 AM

As far as the air cleaner, I have mixed feelings about what is available. K&N has a standard air filter that replaces the top cover with additional filter. From a functional standpoint, this filter would flow plenty of air, however since it is drawing air from inside the engine compartment, the air is hot, which hurts your power. I've seen taller truck filters that have larger openings, but have not seen them in the after market as an option. You would just have to stumble on one from a bone yard. You may be able to find a high flow after market one made for throttle body. The intake for throttle body is the same as a Q-jet. For mine, I custom made a snorkel from PVC pipe. Not sure this is good to do with a non-port injected engine as a carb has potential to puddle fuel in the intake which can catch fire. A steel air cleaner will survive a flame flash, where plastic may not, depending on the type of plastic. I think the best thing is to just do some internet shopping performance parts and see what kind of ideas you can come up with.