Hey everyone, I am getting closer to making a 331 or 347 happen and wanted to get some input. What would be a good combination including carb and cam that will not idle too rough...maybe slightly more choppy than a 268HE competition cam but barely. This is not a drag racer but I want it to be mean on the street and very driveable. I have 3.73 gears and will have a t5 at some point. Currently its a 4 speed toploader. I am running 205/70/14 tires all the way around and would prefer to keep it that way. I will be running hipo exhaust manifolds, no headers. Need to get it as mean as possible for the street but able to drive daily and comfortably. So which motor and what combo? What is the opinion on the pro comp heads?

I don't want to spin the tires off to the point that I lose what I have gained due to spinning.

I would love to be able to get a qtr mile time under 12 seconds, is that possible?

All suggestions would be appreciated!

 

I do not know too much about these two motors so i will not pretend that i do and give you false info. However i will say one thing that i have heard about the 347 and see if other people think it is true or not. Because of the stroke on a 347 the placement of the oil ring on the piston is over the hole for the connecting rod pin so oil can leak by and burn up. I have heard that because of this these motors can burn up more easily and that the 331 is a better stroker. Again this is just what a heard so if i am wrong i apologize. Good luck with the build none-the-less.

 

The oil ring problems with the early 347's has been improved. Unless you're going to drive it 20 or 30 thousand miles a year, I wouldn't worry about that.

The only thing that would keep me from doing a 347 in lieu of a 331 would be if I only had an early 289 block to work with. The shorter cylinders would virtually prohibit a high RPM 347. If you have a 302 block then do the 347. Since you are concerned about lope, the longer stroke of the 347 would help a little in this area. Also always remember "there's no replacement for displacement."

Go 347!

 

205 tires with a stroker motor? i dont know if you will get 12s with the pizza cutters, why keep them so skinny?

 

Don't know what you will be getting torque wise but if it is in the 300+ range, I'd suggest you go wider if you really want to be able to accelerate hard without excessive tire spin. I'd suggest 225 all around if you want the same profile but still want to stay in the wells. If you don't mind a larger back profile, then 225 up front and 245 will give you better grip and doesn't look too radical.

 

I'd recommend a Comp Cams Magnum 280H cam with Rhoads lifters. This is what I run in my 331 and I love the way the motor behaves. Slightly choppy idle, driveable power from 1800+, the cam really kicks in at 3k, and it'll wind to 6200 with good heads. With your gearing, the car will be very driveable.

Silverblade is right about those tires. If you want performance, stuff as much tire as you can under the fenders. It won't be much more, but every little bit helps.

Unless you plan on using giggle juice or a blower and some really sticky tires, don't expect to dip into 12's. I'd expect low 13's with a good stroker build, the right suspension, good tires, and a good driver.

 

Thanks Starfury for the reply. Any reason why you chose the 331 over the 347? What I want more than a 12 second qtr car is something that pull hard on the freeway if needed. Would like a wider tire, especially in the back, but would like the width difference to go inward rather than outward. I believe my Magnum 500 14x6 rims do not come in a version with additional backspacing, unfortunately! That 280H cam sounds like what I am looking for.

 

Any chance that someone makes a 14" Magnum with additional backspacing. Would like to go wider on the tire but keep any additional with toward the inside. Thanks!

 

I would like the tires wide, but would want the extra width added to the inside. Can't find the Magnum 500 wheels that have addtional backspacing to make this happen. Thanks for the reply.

 

Thanks for the reply, will definitely be using a 302 block for the stroker.