APACHE JOHN

Bone stock 1985 LB9 Iroc-Z. 700R4, 3.42 posi..........I've had a 54k mile 1991 L98 in storage for awhile. Souldn't be any problem running this with the MAF and 85 electronics right? would a tune from a 1985 Corvette help? thanks in advance. Oh if I need to run the "ninth" injector I'm not opposed to that.

watajob

iTrader: (29)

IIRC, '85 TPI ECM is a 1 year only, super slow bastard. Try a search. I think you'll find most will recommend switching at least to a newer MAF ECM or, ideally, a 730 speed density set up. Just my

Tuned Performance

iTrader: (92)

if your going to stick with the 870 ecm you should at least use a vette bcc and the ninth injector. Upgrading to the 1227165 ecm would be a huge improvement. you also need to have a flex plate for a 1 piece rear main and 22#hr injectors. If you have the injectors already and they have been laying around for a long time better to just contact south bay fuel injectors and get a set of there bosch 3's

APACHE JOHN

870 is fine by me....my 85 Iroc ran better than most 305's. I know it had the good camshaft and 3.42's. But the 85 Corvette I had years ago ran as good as most aluminum headed Corvettes. I'm gonna go for it when I get the time.

Jim85IROC

iTrader: (2)

I did a similar swap in my 85 and it sucked. I eventually did a 165 ecm swap because it ran so bad. Unless you keep the stock 19lb injectors, the stock computer won't be able to keep the fuel where it needs to be. I think the 85 Vette ran a lower fuel pressure, so just using an 85 vette chip won't work optimally either. You really need a custom chip, but there really isn't a lot of experience to draw from on the 85 chips. That's why I did the 165 swap shortly after I put the motor in.

APACHE JOHN

I know you used some old school heads and some carb type camshaft......yeah I have a good memory, All I'm asking is I shouldn't run it any compatiblity problems. Hell if I had some 85 vette heads and prom nobody would probably know the difference. Most people who make fun of early electronics can't tune there way out of a paper bag. End of of story I'll post no more on this subject.

Jim85IROC

iTrader: (2)

My heads and cam were both pretty mild. The problem was that the 85 ECM had no idea what the hell to do with my 24lb SVO injectors, so it ran pig rich. If your 350 is mild, and you intend to stick with the stock 85 ECM & chip, I would recommend that you stick with the stock 305 19lb injectors, and just bump the fuel pressure a tad to compensate. I've had a couple friends do similar swaps with good results, because the injectors still match what the computer thinks it has, and the BLMs are within range for the computer to compensate.

As an example, when I first ran my 350 at the track, I ran a 16.1 in the 1/4. After I swapped to a newer ECM & tune (and swapped from a 700R to a 5 speed) I got down into the low 14s. I've since run as fast as 13.6 with very minor bolt-on changes. To ignore the tune is just as bad as slapping the wrong carb onto a motor and expecting it to be "good enough". I'm not making fun of early electronics, but you're partially right... I can't tune the 85 ECM. There's very few people with experience on that unique ECM, which made it very difficult to get any kind of an education, which is exactly why I did the 165 swap. There's a wealth of knowledge on that system, which just makes the job of tuning that much easier.

APACHE JOHN

Fair enough and I do plan on a bascially stock L98. If i were to do any swap it would be a LS1 PCM on the L98.

Greg '85 T/A

I thought '85 350s used 24 lb injectors?