My new cam is going in this wed. Since I will have the intake off I want to use some accel runners I already have. Unfortunately I don't have an aftermarket intake base yet. Would the runner swap by itself give me any gain or would I be better off waiting until I buy a different intake base and swap it together ??
What kind of gains could I expect from the runners ??

Thanks
Alex

 

anyone please ?

 

You will still have the restrictive stock base, I would except little to no gain. Porting the base may help some. Its a shame you don't have the base now, rather than having to tear it apart later.

 

Nice car IROC_Vert

What cam are you putting in?

The new GMHTP magazine did a before and after DYNO comparison with SLP runners on a 305. IIRC it was a 7hp gain.
It already had headers and exhaust modifications, and I think some sort of cold air kit.

Personally I installed the Accel Intake and runners on my stock 350. At the time I realized no decrease in elapsed time for my 1/8th mile runs with only a couple of hundreths increase in mph. My stock exhaust manifolds were the hindrance to my power gains. Having said that I think that your exhaust cutouts will allow for some increase in power in combination with the runners and cam. Your intake AND exhaust manifolds will have to be changed to realize much better gains based on my experience.
I would go ahead and change the runners anyway.

 

I would install them, but try to port out the stock base as best as you can (I know there's not much material to work with). I had the Accel runners on my car, but I also did a full head/cam/base/throttlebody swap while I was at it, so I can't really say much about the runners.

If you're gonna have everything apart, you might as well stick em on.

 

I would say install them so that you have an easier time reinstalling them next time. Don't bother porting your base if you're replacing it. If you could hold off on the cam until the base arrives you could save yourself some time and money.

 

It certainly cant hurt to install them if you are going to have everything apart anyway. There is nothing worse than having nice parts sitting around not being used! Just port match the plenum and the lower base and there would have to be a worth while improvement over stock. Unless of course you can scrounge up the money and get the base right away.
Good Luck!

 

I have the accel runners I my car now and i only mildly ported the corvette intake that i put on with them. the car does run better now ( does't die at 4000 rpm like before) and I think i finally got enough air moving thru the plenum the make use of the corvette heads I have. I ported upper plenum to the runners and this required removing about 1/16" all the way around each hole. I'm happy with how it runs now for a 305. Before my best 1/4 mile time was 14.89, I think with the runners and porting I might see a 14.5 pass.