Posted by Chris W. (216.172.142.39) on April 16, 2001 at 05:02:34:
In Reply to: Re: Just take a guess, if you will..... posted by Ken on April 15, 2001 at 20:46:31:
The Cleveland 2 BBL. heads flow alot more air then most stock smallblock heads. I actually have the flow numbers for most SBF heads so I know. But, the 400 is a little different engine. Even though they are small blocks, their size puts them up in the big block range. That's why bolting on a set of 4BBL. heads is an improvement for about 90% of 400 performance builds. I can compare it to bolting on a set of alum. heads to a 302. Good examples of this are the stroker 351W engines that are popular now. There are alot of 392, 408, and even some 435 kits out now. Everyone knows you can't use a set of stock heads and expect them to run very well. You need more airflow to feed the extra cubic inches. The only reasons not to use the 4BBL. heads is if your doing some heavy towing or the extra money. On a 400 (or 351M), it will probly set you back about $450.00 more to use them. The heads are around $350.00 and the adapter plates are around $100.00. They take a little work, but they allow you to use better 351C performance intakes.
As for the carbs., most 400's need the 750. Just as with the heads, they need the extra airflow. Or for some reason, those Holley 650 Spread-Bores (Quadra-Jet replacement carb) seem to work really well on almost any engine I put them on. You could try one of those instead. The only thing wrong with them is that they don't have Ford Kickdowns. But, you can modify a Carter Ford Kickdown kit to work with Holleys.
Your right about the transmissions. If your just driving on the street, a C-4 or FMX will work. If your planning on any racing or towing, especially if it's with a heavy car or pick-up, you better use a C-6. We raced my Dad's Gran Torino (4500 LBS.) for awhile with DOT's and had no problems. When we used a set of slicks, we fried the tranny on our second run.