I went today to price headers for my LG4 305. The guy behind the counter told me I should put a performance chip in. He said this would add about 25HP. The chip he reccommended was a Hyper Tech Street Runner Power Chip PN#12061. Has anyone else tried this with a LG4? I still feel headers ,and 3" cat back would be better ,but can I get good HP increase from just a chip change in my ECM? Would like to get to 240hp . Any feedback on this would be great.:hail:

 

Yes, you can get a good performance increase with a custom eprom - provided you burn it yourself.

"Off-the-shelf" eproms like Hypertech do very little. I suggest doing a search on "Hypertech", "ADS" or "Jet" and read up. Anyone that has look "inside" can attest that the changes are very minnimal and a complete waste of money.

Frankly, the FIRST mod you should consider is getting the eprom burning equipment and learn to tune your engine. The best time to learn eprom burning is on a basically stock engine - and even that can get a nice performance increase along with a lot of other benefits like improved driveability and better gas mileage.

 

Buy Doug Roes book on the Q-Jet, and you can make a difference, changing a chip on an LG4 hardly matters, with a stock carb.

 

I was quickly answering a bunch of similar questions (off-the-shelf eproms) when I replied to this post. I missed the LG4 part.

Yeah, I agree with Bruce. The LG4 chip does very little, mostly timing - that's about it. Waste of money period.

 

You will definitely get more out of headers & a catback than an aftermarket prom. While you might be able to burn a PROM & see good gains on the LG4, freeing up the exhaust is a big gain. The LG4 & L69 exh. manifolds are smaller than the TPI ones.

I have run an 87 G-body L69 w/ and w/out aftermarket prom. I have run an 86 G-body L69 w/ LB9 injection w/ and w/out headers, and based on all the miles I've put on the combos... the headers are the way to go.