I have a 305 LG4 engine in my 87' Camaro Sportscoupe. As you know they dont produce much HP. I believe 165HP. What type of intake manifold do you guys suggest? I was thinking of going with a Edelbrock performer intake. Also will I need to change my factory cam to accomidate the change. Can I still use my quadrajet carb until I can afford a better one? Just looking to get some more speed out of this thing. Would rather have a IROC or a Z28. Any suggestions?

 

Don't waste your money on an intake manifold. It's not the problem with that motor. The way to cost-efficient speed is to find the things that hurt the performance the most, and fic them; it is not to simply unblot ane swap out things up on top that are in plain sight and easy to get to.

A L69 (HO motor) dual-snorkel cold-air intake makes a noticeable SOTP difference. Get one. It's worth probably a good 5HP, and takes about 15 minutes to install.

The first problem with that motor is the exhaust, all the way from the heads to the street. Get a set of application-specific headers for some other car, I'd recommend asking for parts for something like a 88 350 TPI. DO NOT get ANY exhaust parts that are compatible with anything you now have; if you do, you will be preserving all the built-in restrictions. Get the headers from SLP, Edelbrock, Dynomax, etc.; a Catco or Carsound or Dynomax cat; and a cat-back exhaust. Do the whole thing all at once, since none of it will hook up to what you've got now.

The exhaust by itself will make very little difference, maybe 10-15 HP if you're lucky; but nothing else will make any difference at all until you take care of it.

The next problem is the cam. You probably have a roller motor but the factory cam is nothing but a copy of the ridiculous "peanut" cam. Look for something with about 210-215° of .050" intake duration, about 10-12° more .050" exhaust duration than the intake, about 110-112° of lobe separation, and the steepest ramps (fastest valve action) you can find. I'd recommend the Comp XE262H which is known to work well in that motor. Get a timing chain, valve springs, retainers, & keepers along with the cam. Replace the stamped sheet-metal stock rockers with something decent; I'd recommend the Comp 1412 roller-tip steel ones, they're a very good value.

After that, the next bottleneck is the heads. If you're ambitious, while you're doing the cam thing, pull the heads and port them. Get the Standard Abrasives porting kit, it comes with excellent instructions.

These 4 mods will put you at close to 240 HP. Your factory intake will support close to 300 HP, so after these other things have been done, it might be time to think about upgrading it.

 

Exactly what he said. I would recommend the Hooker Cat-back.

 

OBTW -

something better than a grocery-cart rear gear will help dramatically too. You probably have 2.73s in it now. 3.42 or 3.73 are the ticket, except that you'll have to get either a 3-series carrier (posi if possible of course), a spacer (yuck), or the special thick gears (double yuck).