Well, my crate motor only has 58cc chambers...

 

Regardless, 12+ compression is not realistic on that motor. Even with aluminum heads and flat tops, I would imagine it would be tough getting over 10.5:1 without a lot of work. I had a lot of machine work done to both the block and heads, I run edlebrock heads and have a solid 11.25:1 compression. Honestly, for my elevation, its too much. Its a cold blooded motor and runs poorly, until reaching at least 160 degrees. I've since needed to run a 50-50 blend of 91 and 100 unleaded race gas, or it pings and after runs. 91 is the highest pump gas octane here in AZ. For your purposes: stock type cast heads, cast or hypereutectic pistions, minimal to no decking, normal head gasket should net you 9.5:1 ish compression. I realize there is more variables, but that is a more realistic number. 12+:1 would most likely require an HD starter as well. I have one and literally no clearance between my starter and headers, and I would expect the starter to fail before anything else does.

 

I have no idea man, I just used Google to find what I could about it. It's actually rather difficult to find detailed information on a 1987 L98 engine :/ I assume if I've made an error, that's where it was.

Straight from the horse's mouth.

Edelbrock.com - Cylinder Heads - Chevy - Small Block - Performer Corvette (1986-1991)
These are the heads I bought.

 

stock compression for a 350 is 7.9:1. im running a mini hitachi high torque starter from summit. good for up to 11.0:1, and was about $180. 305 heads are 55cc or 58cc

and the info on edelbrock's website even conflicts itself as to which intake manifold to use. 86 uses straight bolts, 87 up uses angled...

what are you using for the bottom end, just the stock L98? with or without rebuild?

 

Bone stock- it's not rebuilt, but I don't see a problem with having it done if it's necessary.

I was under the impression that the compression ratio in an L98 was 9.5:1 from the factory?

 

Why didn't you just go with a rebuilt long block? Then you would have known the cr

 

Because I don't know anything?

I'm filling out the order sheet at PCMforless.com

Here's what I'm putting in, if someone wants to double check this stuff for me?

 

broadcast code i think is the digits already on the chip. you need to remove the ecm from the dash and take off the little plate and write them down.

you said fuel injector size was 22 lb, which is not stock

stock thermostat, or will you go with 180 (i highly recommend a 180)

for the exhaust, have it setup for shorties and no cat for now instead of sending the chip back later for adjustments.

i wouldnt bother saying what intake you want to use later. when you get the new one, the chip will run with it until you want to maximize power and send it back to be retuned.

for the cam specs, copy and paste the matching info from COMP Cams 08-408-8 - COMP Cams Xtreme Energy Camshafts - Overview - SummitRacing.com

and i see where you are getting your info for the 9.5:1 CR. i would highly suggest just having the bottom end rebuilt and find out for sure what pistons are in it. take some pics when the heads are off. if the bores still have crosshatch, just do rings and bearings. more than likely they wont. but using those heads the compression will probably still be very high

 

Alright, will do.

I filled stuff in like you said- just a couple things left. I'm not sure what to put in for Cam Advance. I obviously don't know for sure what my compression ratio is going to be, and I need to know where and how to get at the ECM so I can get the broadcast code.

 

Cam advance should be zero, unless you have someone professionally advance it. I have heard that it isn't hard to do, but from what I have seen it looks very complicated and requires a degree'ing wheel and what not. with the smaller cc heads (stock 350 heads were probably 64-67 cc) you will be a little bit below 10:1. which is good, because above that you need race fuel. I would just say 9.7:1 ratio, and the chip should be able to work with that. And for rebuilding the engine, AT LEAST get it reringed. I have been told that after 80k miles DO NOT do major performance upgrades or you will spin a bearing. I would not just throw a 100K mile motor in after putting $3000 in upgrades and parts without rebuilding the block first. The stock pistons will be dish topped and you will need that for your smaller CC heads. Please have the block redone :/

to get the prom out, DISCONNECT THE BATTERY. You do not want to be playing with all of that important computer stuff with the possibility of shocking it and frying the whole thing. unscrew the plastic covering under the passenger side dash. I believe it's a 5/16ths bit? a little fella. then get on your back and look up inside the big hole. you will see an aluminum box about the size of a textbook, get it out. It will have 3 big wire connections on it, and you will probably have to push it up then towards the motor for it to clear the little holding bracket there. After you get it loose, you will see a little cover that has 3-4 small bolts on it. this will be on the opposite side of the wire connections. take those off, and you will see something that looks like a RAM card held in just like RAM cards are held in on a computer. I don't think you have to take it out to get the numbers though. they should be printed on top.