Carb wanted

I am looking to buy a downdraft for my 327 AMC. Should be 600 CFM. I prefer a unit that is ready to go as opposed to one I need to rebuild. Holly would be preferable but would consider an Edelbrock.
Thanks

TRBenj wrote: Jack, you sure you need/want a 600cfm? What kind of hp and rpm are you talking? The 220hp 302's used 450cfm Holley's from the factory. I have Rico rebuilding a few 600cfm Holley's this winter, believe we have some 450cfm's that could be done as well. Once we're a bit more organized we may be able to tell what we need to keep and what could go. Pm me in a month and remind me!

I will be in touch Tim. Honestly don't know what I need. My neighbor is an old timer. He was a Chris Craft mechanic. He say's all I need is a two barrel downdraft. Probably the 450 is more appropriate. This is a 188HP.

I have a Gray Marine Fireball 327 / 220 hp and run a Holley 600 CFM on it. It runs well with that carb. I think the original 4bbl option on the 235HP engine was 600 CFM, if memory serves.

The majority of marinizers using Holley's didn't use wedges to flatten out the carb mounting angle (including PCM) and they run just fine that way. I believe the AFB/Edelbrock carbs are much more sensitive to angle though. Something to think about!

I am totally unfamiliar with AMC's but the hp difference between 2bbl's and 4bbl's is usually only partially attributable to the intake and carb... many times, heads, compression ratio and cam are different as well. Just don't expect to go from 188 to 235hp unless you identify and upgrade all the necessary parts.

Jack, a 600 CFM Edelbrock with wedge runs great on our 312. However, it is big for it based on CFM calculations. 450 CFM is more appropriate based on the calculations.   If Tim can get you a 450 Holly to try, give it a try.

Can someone please clarify what is the difference between a vintage carb say from the 60"s that is marinized or the auto version. Been told the only difference is the flame suppressor but that doesn't sound right. J tube?

8122pbrainard wrote: Jack, Whoever told you that the addition of the flame arrestor to a carb to marinize it back then is correct. J tubes came later.

Before the j tubes came slabbed throttle shafts

In this old thread there are pictures of an automotive and a marine shaft.

This all pertains to Holley carbs and I don't have a clue when they started with the slabbed shafts but it was definitely before the j tubes showed up in the second half of the 70's.