The Stovebolt Site Forums The Shop Area The HiPo Shop Increased performance from a v6

Since my engine is low mileage and will probably outlive me, hopefully I'll never be opening it up.

But I was wondering what could be done to increase the performance of a v6? I've read about better carburetion, dual exhaust and HEI distributors, but what other things could be done if completely rebuilding a v6? Port cleanup? Mill heads for higher compression? What type of gains in horsepower could be expected?

Scott

what V6?

GM? Ford? Dodge?

If GM, which one?

60 degree V6's - 2.8 liter, 3.1 liter, 3.4 liter, 3.4 liter twin cam)
90 degree V6's - 225 Buick, 229 Chevrolet, (3.8 liter) 231 Buick (3.8 liter), 4.1 Buick, 4.3 Chevrolet, 305 V6

Lets assume the 4.3 liter V6. Forget milling the heads, start with a set of Vortec heads (96 and later). Since your talking HEI, your running a carb. Use a dual plane intake and a holley 390 cfm carb. There are plenty of cam options out there. I have seen this engine putting out 300hp without breaking the bank. Other than that, think of the engine as a SBC with cylinders 6 & 7 removed.

If you're talking about the GMC V6, there's little, if anything that can be done to improve the performance. It's basically a low RPM, high torque load-pulling engine, with little or no emphasis on fuel economy or high speed horsepower. For one thing, the rotating assembly is big and heavy, and very suceptible to destroying itself from vibration if strict RPM limits aren't observed.

The machine shop where I ran the connecting rod reconditioning department used to sort of specialize in the big V6's, and even swapping a crankshaft from one block to another, or substituting rods from another engine could create vibration problems. They definitely didn't like any effort to exceed the reccomended top speed. There's a reason the big six in my fire truck has a tiny Stromberg 2-barrel!
Jerry

Anything that a V8 responds to, a V6 will too. Best places to look are in the air and fuel department. Better heads, better compression, better cam, better intake, better carburetion, and better exhaust.

How much? Well, you can't do the funny math like ricers like to do. You know, this intake is worth 30 hp and this decal is worth 10 hp and this rear wing is worth 15 hp, etc.
It is the combo package and they all feed off each other. I'll bet on a mild V8 engine, if you did all of the above, you'd probably see 40 or 50 hp out of it. With a V6, figure 75% of that.

But my favorite way of making a V6 stronger is with turbochargers. Look at the Buick Grand National. Nothing wrong with that engine.

So, how many mid-1960's GMC V-6's have you modified, Hot Rod Dad, and how much gain in performance did you get? How about sharing some torque and HP numbers from your dyno tests? I've probably built, or at least machined the parts for 50 or more of those engines, all the way up to the 400+ cubic inch ones. They do not respond to hot-rodding tricks- - - -they just come apart!
Jerry

I built a 330hp Buick for my Opel. All naturally aspirated.

Could you clarify for us what V-6 you are thinking about?

If you've read this far its pretty clear its not clear to those posting responses. Some are sure you're dealing with the old GMC truck V-6 (my own guess) and others are assuming later car type motors.

Which V-6 do you have in mind?

60s GMC V6s, 305, 351, 401. 7.5 compression, 2 barrel, single exhaust. Limited to about 3600 rpm.

http://www.6066gmcguy.org/performance.htm

The large bore / short stroke should allow for higher RPM, however the engine was limited to 3600 RPM. The oiling system and coolant system are not intended for high speed. The pistons are rather heavy, along with the remainder of reciprocating parts. It is a high torque, low RPM truck motor from day one.