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pullmytrigger
03-08-2010, 11:16 AM
I have this alum head 400 sb that I was going to swap in my 85 3/4 ton 4x4 Sub for some extra power for towing.....boat with all our chit and gas wieghs just under 9000lbs......the bone stock carb 185 hp 350 that is in it only has about 50,000 orig miles runs great but not enough power.....guys are telling me you can make plenty of power with a 350 built for torque...anyone ever actually do this?....then I could keep the 400 for the racecar.

MILD THUNDER
03-08-2010, 11:24 AM
My guess is, you will be able to make more power from your 350, but in the long run, a big block would be the way to go for pulling power in a heavy truck, with a heavy trailer. I bet installing a gear vendors splitter on the back of the trans and splitting up the tranny ratios would give better towing abilitys rather than camming up and adding HP to the 350.

I am in the semi dump truck business, and when it comes to hauling heavy loads, a 350HP mack with a 10spd trans will out haul a old 350 mack with a 5 or 6spd trans all day long.

I am looking at some old 454/TH400 duallys, and rather than beef up the engine HP, i may go with the gear splitter, as the old TH400's 3spd ratios arent that great. The new diesels with 5spd auto's tow awesome, most give credit to the power of the diesel, but alot of it is in the 5spd tranny.

Uncle Dave
03-08-2010, 01:45 PM
A set of real heads (brodix, AFR) and an intake kit will get you to the 350 HP 300lb/ft level, pretty easily.

There are tons of combo kits available, and many guys just buy a budget shortblock for about 1-1.5K and bolt the new top end pieces and old accessories to it that way your are refreshed completely but with 50K you should have some life in the bearings. (unless youve been beating and heating it )

Better yet would be a 383 stroker kit shortblock and top end combo.

9K is a boatload of weight, youd better get a weight dist hitch, real brake controller and an anti sway mechanism.

Your stock radiator and trans cooler will not be enough and you will need to replace them with better aftermarket units and preferably run an external trans & oil coolers.

The gear vendor advice is excellent, but expensive and a job to fit.

a BB swap out would be great -but that is a really big with mounts and clearance issues vs. a small block refresh.

I have a 406SBC in my boat and it makes a true 500HP and 475LB ft- they are screamers.

UD