Reply to "4 x Weber 48 IDF (not IDA) conversion"

George and Dan hit it right on...look at the size of the Weber venturi times eight, then do the same on a 750, 850 or larger Holley...the volume flowing through the Webers will be greater how there can be restriction I don't know.

I had a McLaren M12 Can Am car that I vintage raced with a little 6 litre small block Chevy with Chevy's best competetion heads ported, using 48 IDA's choked down! to 42mm for better lowend power, (I would guess the heads didn't flow as much as the 351C ports just because they were physically smaller). That Chevy small block ran like a scolded ape and was probably putting out (only) 550-570+/- of very usable power, no flat spots and pulled like a son of a gun from 2000 rpm up to 6500 (what a rush with the acceleration and sounds!), redlining at over 7000.

At the very serious vintage events where you had Porsche 917-10's with legends such as Folmer and Ginther driving (they drove the cars for Vasek Polak team in the actual Can Am series) I had Dick Smith drive, famous for driving the winningest SC 427 Cobra in history(a Ford factory effort) Dick Smith still owns #198....he said he couldn't believe how hard the car accelerated through all the gears...he said "it accelerates as hard in 4th and 5th gear as it does in gears 1-3". Of course the car only weighed 1700-1900 pounds (depending on fuel weight) which allowed the horsepower to be put to the ground through 16 inch wide Goodyear Eagle slicks (Dan's comment about the weak link/fuse, ie: transaxle and tires is very appropriate...great analogy Dan!). We built the motor for usable horsepower (not peak horsepower from 6500-7500 rpm) on road courses so that it wouldn't break every other time you pulled out of the pits (which most of the other cars were doing). I also chose not to go with a big block...more weight, worse handling. The motor never broke nor did the LG 600 transaxle that was put behind all the big block motors. Dick Smith also drove in the Can Am series in an identical McLaren M12 with the only "Ford 427" (don't recall if it was a mid or high rise motor) run in the CanAm series and the car CONSTANTLY broke the same LG600 transaxle because of the massive torque from the Ford 427...this wasn't a problem with the big block Chevy's (less torque I assume) which dominated the series until the turbocharged 917's (turbo 5 litre) came along.

If the LG 600 Transaxle (straight cut gears, non syncro box) had problems with the Ford 427 torque, the ZF will absolutely disentegrate if you can get tires to hold the horsepower and the additional 1200 pounds of car...I don't think there is enough wheel well to put that much tire on the ground, however.

If you go with the 427 with the Webers, (WO BOY what fun!!!) take some drifting/driving courses because my guess is you'll be spinning tires up into the 80's (mph)easy in a straight line and well over that in the corners.