SBC, boat, approx. 550hp, gas, 4bbl. 1,200 ft. elev. "Carb Shop", is saying a 200 gph. mech fuel pump is neccessary. Biggest "Carter" is 172 ? How much is enough ? Max power should be no "fatter" than 12.8/1 afr. ? Thanks, roverman.

Per the "Tech Tips from the Professor" article in a typical Summit Racing catalogue, his fuel pump sizing method is based on the following:
At WOT, an engine requires 1/2lb fuel per hr per HP and 1gal gas =6lb.
So, for a 550HP engine,
fuel pump gph=550x1/2lb/hr
=275lb/hr
=275/6gph
=46gph
Based on this method, your carb shop recommendation seems high but you might want to have an independent look at this logic.

Math correction made...must have been that last beer.

The old standby is ... Hp x 0.23 + GPH

Use more if using a bypass style regulator or planning on drag racing.

You sure they didn't say a 200lb/hr pump?
Take a look at something like this - which is plenty for a 550hp carb'd engine:

http://aeromotiveinc.com/products-page/fuel-pumps/11103-tsunami-fuel-pump/

Look at the flow charts.
A 200 gallon pump would be 1200lbs/hour!

I was thinking something like this..
http://aeromotiveinc.com/products-page/fuel-pumps/11213-ss-fuel-pump-orb-08/
With a deadheaded regulator.
http://aeromotiveinc.com/products-page/regulators/carbureted-regulators/13201-ss-adjustable-orb-06-regulator/

Thanks all.  I'm thinkin, they we're thinkin, Donald will be makin more like 500 hp, of which 200 lbs/hr. would be right there. Graham, when I do the math, 550 hp. X .5,(1/2), I get 275 ?  Tony,  HP X .23 + GPH. ?  I don't know the GPH. How do I add an un-known ? Thanks for the refresher.  roverman.

Art,
         Damn, you caught me with a math error...sheepishly corrected above.

Sorry Its been a long week.. formula should read
HP x 0.23 = GPH

Ok, with "Graham's" formula, 45.8 gph/550 hp. "Tony's" formula, 126.5 gph./550 hp. Anybody else want to dable in the mistyque ?  roverman.