braekedaun

Allrighty ya'll, first post. I've got a 1989 camaro IROC-Z that HAD a 305 TPI engine that IS sitting on the floor now. The new engine is a 96 LT1 test mule out of a caprice. I got the documentation on it, test motor with about 500 miles on it or so. I put a GM performance intake on it, but other than that its a stock LT1 with the cast iron caprice heads that make more torque than horsepower. Its strong, but not fast. I've got a quadrajet on it from an old Caddy. I rebuilt the Q-jet and put rods in it (internet recommended) for the smaller engine size of the 350. I think my secondaries are not opening properly, but my dad (who messed with Q-jets when it was new technology) says its a timing issue. Its my understanding that the Optispark was computer controlled and advanced, so there wasnt "engine base timing" on the original engine, and I beleive I was told that there had to be SOME advance on it to make it run right. The usable range of throttle that will keep the car running is very small. When its cold, I have to baby the heck out of it and feather the throttle ALOT!!! Once its warm, it runs better, but I can only give it throttle slowly, and if I give it too much, it loses power and gasps, then when I let off the throttle again, it goes good. It smells rich as hell when we come to a stop. I probably have only about 1" of usable throttle travel without boggin it heavily. It will only take full throttle once the engine is warm and you let the RPMs get there slowly, then apply full throttle. Can someone give me an idea on what base timing should be set at? I've went from 0 degrees to 10 degrees and I cant seem to figure out what the deal is. I think its at 8 degrees now. I've got right at about 6 psi going to the carb (idling), and I swear sometimes it acts like it doesnt have enough fuel (long acceleration) and will kinda choke out. I've got the standard camaro fuel pump in the tank with a fuel pressure regulator (mallory - return style) in place. I've installed a Mallory perfomance distributor (pn 4748201) which has been good, but I've replaced the darn ignition module in it 4 times in 500 miles. At least the company will send more for free and I have an extra one now. I can change it in a few minutes on the side of the road NOW! The optispark hole was plugged in front with a GM part with timing marks on it. Oh yes, I almost forgot. Can I just bolt on some LT1 aluminum heads for much better perfomance, or do I have to swap the cam out too? Is there a snowballs chance that the 305 HO heads from the old engine would work on it? SOMEbody told me they'd work AND increase compression a little. I'm sorry if I've missed some valuable information here, but I'll be happy to track it down or check something if I need to. I'm just about ready to throw the Q-jet in the garbage, but I'm not 100% sure thats what the problem is. I appreciate your responses and look forward to new insight! If there is anything I need to get to better inform you, please let me know! Thanks, Matt

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chevyowner02

The 305 heads WONT work the LT1 has reverse flow. You can get a set of aluminum heads. Do you have the dist 180 out?

braekedaun

it woudnt run at all then at 180, would it?

I got it running a little better screwing with the secondaries set screw. They were just barely holding closed, and now they dont open until the last minute. We also advanced the timing more - I dont know whether we were off with finding top dead center, but it APPEARS to be about 20 degrees advance and its running better than ever. I can only guess our initial 0 degrees mark was off for that to happen. It kept backfiring before, so we advanced it more. I have not had a chance to get it hot and run it, cuz its raining hard and I have leaky t-tops.

Has anyone else removed the vacuum assist for the secondaries? My dad was saying that the old ones didnt have it, and you could set it where it would just "WHAM" open up and kick you in the seat of the pants.

chevyowner02

Yea it will run 180 out,run like crap bring #1 to TDC pull off the dist cap and make sure it's pointing to #1 cly. It may not be your problem but if not you can eleminate it.

braekedaun

apparently most of my problem was timing. It runs like I'd expect it to for the most part now, except for whether the secondaries are opening or not - I THINK, but I'm not sure. Before they were just hanging open too soon, but now I think they're not really opening (but the engine is much stronger now!). It should be noticeable when they open, shouldnt it?

Somehow our mechanical method of finding TDC was off, because I'm showing about 20 degrees of advance. I know thats WAAY too much realistically, so my measurements must have been off in the first place.

chevyowner02 - I did check it - it looks good.