After I do a little work on the exhaust side I think my next step will be to port the plenum and add either AS&M runners or an Edelbrock base. Neither are very cheap so I will probably have to do one at a time. I was going to go with just a base, but then I read that the stock runners are actually a bigger restriction than the stock base. So should I add the runners first? Will either of these pieces yeild big gains without the other? I'm a little leary of spending hundreds of dollars with only a couple of tenths off my ET. Anyone with experience? Thanks.

 

I fitted the edelbrock base to my 305 without AS&M runners. I don't believe for one minute that I'm getting the full benefits from the base as is so I'm getting the AS&M long tubes and a 52mm throttle body and port matching and porting the whole lot. On its own you wont see a great difference, but as a package it should be nice. Also remember that you'll shift the pwoer a little higher up.

As for not wanting to spend hundreds for a couple of tenths, look at it this way. All of the few hundred dollars and al of the tenths all count up until you have taken a couple of seconds off your et. When you take off a couple of seconds you seem to forget how much cash and hard work it took to get you there.


Rob

 

I have data (from an old Corvette Fever article) on mods to a '90 Vette L98 that shows the BM base & LT runners combined with a 52mm TB and ported plenum were worth .8mph at the big end and .19s off the ET.

Have you considered siamesed base per this link:
http://www.geocities.com/softtailduece01/
I think Mad Max on this Forum did this mod with success.

I am in the process of doing a similar mod to a used stock base and putting AS&M runners on top for my '88 Vette. I have dyno pulls from last fall and will get some as soon as possible after this mod is in. If it doesn't work out I can still go with the BM base and only lose about $100 and some time.

 

Jim,

Are your runners the long tubes or the semi simased? I think I'm going to try that with my old base now

Thanks

Rob

 

The AS&Ms are LT runners. I noticed from test data in TPIS "Insider Hints" some low end torque loss with siamesed runners.

On a recent trip to Mesa, AZ I stopped in at AS&M and was impressed with the quality of their products so I now have a set of their LT runners to go in.

I know what you mean about the stock base, if it realy works. I would rather have the 30-40hp gain for ~$100 than the 10-15hp gain for $400+.:cheers: