The Stovebolt Site Forums The Shop Area Engine Shop More grunt on my 351 v-6 motor

I need some info on what I can do for more grunt on my 351 v-6 motor.( check out my 61 fire truck in the gallery) I race 4wheel drive trucks in 300 ft sand drags and have recently purchased a 34 FT enclosed trailer that has living quarters and enough room for my full size 4wheel drive truck. The 351 does not do bad but it takes a while to get this rig to freeway speeds of 55-60 mph. What can I do to get more grunt? Did anyone ever make a triple duece or 4 barrel intake? What kind of cam? Headers? Any Help would be appreciated!
Mike K

You could drop in one of these................ Twin Six

I think Jolly is our resident expert on these; hopefully he will jump in with more info.

What gears are you running?

Parts for these are getting hard to find. They also suffered from balance problems, and were easy to scatter pieces all over the blacktop. Any work would probably require a good balance job with the crank lightened. Two websites to look at.
GMC Pauls and Jolly\'s 60-66 GMC

Fred T, you beat me to it! I was looking for the link to his main page to put on there, then I just backspaced it and got there anyway.

Tune up specs for GMC V-6

I am not sure on the gears. I will have to check it out.
Mike K

6-71 blower! Giddyup.

Theres not much you can modify on the V6's. Your pretty much stuck with the intake manifold, which only leaves you with two barrel carbs. You can probably put headers on it, but watch the RPM's on the v6's. its easy to throw a rod through the block. The 305 has a max of 3800 RPM, so the 351 cant be much more than that. Trying a different gearing would probably be a safer bet.

I guess that if a guy really wanted to make the 351 go faster he could weld his own manifold. Make one that would take a big squarebore.

Jonathan's right on the rpm issue. I drove a lot of 2, 5 &10 ton trucks with the v6 in the 70's. Lots of raw torque, but not as much in the top end as needed.

The 478 had a lot more power, but it red-lined at 3250 and would not last very long at that speed. one truck we had was geared to 62 mph tops, and in 100,000 miles we blew 4 engines since it had been declared a road truck. It was a '73 model that was retired in '75. The last engine in that truck left a piece of block on the road that was as big as the palm of my XL hand!

The only good way to get more rpm and power out of the v6 is to pull it and drop in a big block chevy.

Yeah, you could add a bigger carb, headers, and normal hot rod stuff, but you'd run out of revvs before it would make much of a difference.

Kind of like the International Scout 304 engines. No 4 bbl intake or perf parts available. They have such a long stroke, and poor rod/stroke ratio. They pop the weasel if revved over 4 grand.

chip

Thanks for all the info! Looks like I am stuck with slow speed unless I bolt in another motor. Any suggestions what a bolt in replacement would be for this motor? Thaks again!
Mike K

Find a Vortech BB. I belong to a JR Fuel team. We were pulling the race trailer with pumped(?) 440. The Vortech just puts the 440 to shame. The race trailer is some were around 17k pounds. The Vortech will pull the trailer up the grapevine at 45 mph, cruise at 65-70. This is a stock vortech in a 98 3500 Chevy. I'd have a tough time beating my Dads Vortech in his 99 RV with my 292.

Larry