Got my car dyno’d the other day at a local shop, and it looks like there’s a few decisions up ahead for me.

For starters, here’s a partial mod list, along with the dyno sheet:

330 HP 350 HO crate motor from GM
Edelbrock Vortec base
Stock 90-92 TPI runners, plenum, throttle body
Stock SD ECM
Long-tube hooker headers into 2.5” true duals (I have a Monte Carlo)
No AC
2004r with WAY too high of a stall converter, as it’s flashing a little about 3200 RPMs (I had the stall from a different motor combo)
3.42 gears






I figured the stall was way too high as it would flash right up past 3000 RPMs with anything more than decent throttle, and seems to be missing most of my powerband as they couldn’t get a reading below 3500 RPMs. I talked to Edge Converters yesterday, and they recommended a stall in the 2400-2600 area, which is on order right now.

I’m also in need of a tune, as from what the shop told me the car really needs some work in terms of A/F to be spot on. I’m definitely getting the car tuned, but I’m debating getting a set of SLP runners beforehand, and if I’m going with SLPs, it looks like I need to port the plenum and possibly the base as well. This could get expensive fast.

The car does seem to be making HP power up to about 5000, but torque starts dropping a little after 4000.

Seeing as this pretty much a “crusing around” car for me with some time at the track a few times a year, what would you guys suggest I do? No problems with driveability right now, but I'd like to get a little more out of my car.

Getting the car tuned is definitely going to happen, I’m just not sure if it’s worth the extra cash to get the SLPs and then have everything ported beforehand in terms of gains vs money spent, as Im not sure how much more I'll be able to get out of this combo.

 

If you have stock runners and a stock plenum you are def giving up power. I would either get a set of SLPs and port them or get a set of AS&M runner and def port the plenum. I have a 305 with a LT4 cam, headers, edlebrock lower intake, AS&M runners and a ported plenum and i made 216 at the wheels...and thats a 305. If your making only 224 at the wheels with a 330 horse 350, there is more to be had for sure.

Edit: Just looked at your Dyno graph. Notice how your torque start to drop off at around 3500rpms and horsepower falls off around 4700. I dont have my graph to look at but i know that my car was pulling all the way to 5000rpms. The stock plenum and runners are killing your power by not letting enough air in.

 

Buy and install ALL of your parts before tuning the PROM....

Get a decent 2,200 - 2,600 converter

You need bigger runners and throttle body. You don't have to go hog wild on the porting, just buy a carbide diamond cut grinder bit and port match to the gaskets the runners/plenum/vortec base yourself.

Then have the PROM tuned.

Doing the above should at least get you to 250-260hp and close to 300tq at the wheels.

 

Yup, I ordered a "Street Edge" converter from Edge yesterday that's rated for a little under 2600.

I know that the SLP vs AS&M-type runners has been addressed a ton in this forum, but does anyone have a suggestion as to which would be better for my particular application?

I've read that the large tube runners flow better "out of the box", but that with a little porting and siamesing the SLPs can flow just as well if not better.