DeTomaso Mailing List: March 98, Message #30
     



From: 	William King <wpk@fc.net>

Subject: fuel system question

Date: 	Sun, 1 Mar 1998 21:46:20 +0000



Hi All,



Can anybody help out with some advise on a curious problem I've

run into since bolting on a FPP intake ?



Here's the background:

	Mildly built 351C, closed chamber 4V heads, FPP manifold,

	Holly 600 CFM Carb Shop blueprinted double pumper,

	mechanical fuel pump, high quality valve train with

	Crower roller rockers and 3 coil springs, mallory unilite.



Problem:

	Car runs b***s to the wall till it hits about 6100 RPM,

	then abruptly loses power. Not sure whether I'm getting

	valve float, fuel starvation, or what. Observers following

	me report white-ish exhaust at this moment and suggest a

	possible lean condition. The subjective feel of the car

	when this happens is like a sudden stuttering/fluttering

	sound interrupted by intermittent very short attempts to

	make normal power followed by power loss again.





Could the carb be too small and be causing enough of an increase in

manifold vacuum at high rpms and WOT to cause the power valve(s?) to

close, causing a lean condition ? I believe that the Carb Shop

literature claims the 600 HOLLY they sell flows about 650-700 CFM.



Or, is this typical of valve float ?



Or, is my ignition not keeping up with things ?



Or, ????



What methodology can I adopt to diagnose this problem  ?

The FPP really starts coming on at 4-5K and if I could just get it

to stay on till 7K ... (:>)



Cheers,

William