Carb size

[NUTNDUN]

Hi gang,
This is my first post and I had a question regarding what size carb to go with. The truck is a 72' f100 shortbed 2wd. The motor is a redone 351w stroked to a 398. It has 11:1 comp, twisted wedge high port heads, mechanical roller rockers 1.7, 2" primary full length headers, super victor intake, the cam is being swapped out for something a little milder but not much. The cam that was in it was a thumper for the drag strip in a mustang with some crazy lift and duration. I don't know the exact specs on the cam that we are going to go with yet. I wanted to see if I could get some suggestions on what size carb, it is a square bore. My one buddy thinks I should put a 1050 on it but I would think that it would be overkill. Maybe an 850? I also don't know what size stall converter yet either. It has a c-6 and I am guessing somewhere in the 4,000 range.

[My427stang]

Certainly a healthy motor.

850 or 1000 (or 1050 Quickfuel) all run about the same size with 1 3/4 plates and very little difference in venturi size. All of those would work well. The numbers are all advertising numbers

Another option would be what they call a 950, its a 750 body with an 850 baseplate.

I personally would would go with a QFT or AED 950, stay away from the Holley HP series, I have had nothing but metering block calibration problems.

One comment on your hint to a possible cam swap. Be ready that if you swap cams, with 11:1 you need late enough cam timing to manage dynamic compression ratio. Its real tough to have any compression and mellow out the low end. As a reference, with 10.7:1 compression in my Mustang, I needed a minimum of 288 advertised duration intalled at 106 centerline, you'll need at least that, and maybe slightly later centerline if you decide to go milder than what you have.

[NUTNDUN]

I wouldn't mind keeping it wild with the cam but I am guessing the cam I have wouldn't be right because of the weight differences. The motor was built for outlaw class I think and had to be under 400 cu. The car it was in before it was freshened ran mid 8's. I wouldn't mind using the cam I got with the motor but do you think it would be too much for the truck? I will try and get some numbers from the cam, it is all sitting down at my buddies place. I do know it was a crane cam with 270+ lift I believe. I forget what the duration was.

What about proform carbs?

I forgot to mention that we had the pistons fly cut to lower the compression. The compression was at 14:1 with the above mentioned cam but I didn't want to be buying racing gas all the time. So we had the pistons flycut to flattops.

I apologize for not knowing exact numbers, I have been out of hot rodding for so long I forgot everything. Now I just know enough to get my self in trouble and spend money LOL.

[NUTNDUN]

I got the cam specs.

it is a crane cam with a 106 centerline.
intake is 276 @ 50 with 672 lift w/1.6 roller rockers
exhaust is 279 @ 50 with 672 lift w/1.6 roller rockers

The cam is a little wild to be in the truck but I am trying to get the truck back together on a budget and I plan on swapping the cam out later if it turns out it just aint right.

I contacted the one fella at prosystems and he recommended a 4150 with 830 real cfm on the wet bench.

[willowbilly3]

It sounds like a screamer and since it does seem to be purpose built for that I would say 850 min. Maybe a pair of 600