I want to put the 87 carb top end on the 350 tpi block thinking about using a edelbrock peformer and holley street avenger carb whice part number on these should i get how hard is this swap whats involved? How much power with that setup will i get over tpi?

 

The Performer intake is 3706 for the EGR version, 2104 for the non-EGR version.

You have the LG4 top end, correct? Why do you think you need a Street Avenger carb? That would be $380 flushed down the toilet for absolutely zero performance improvement and certain economy reduction. To say nothing of the additional costs (~$300) to just get it to work with the rest of the car.

Forget the SA carb, stick with the q-jet. That will be the least amount of work, provide the most benefits, with no reduction in power.

How much work? It's basically a matter of removing the engine, transferring the LG4 pieces onto it (and installing the new intake manifold), and re-installing the engine. Of course, while you're at it, you're going to upgrade the air cleaner. Combined with what you already have (headers, exhaust) it should yield you a good 50 HP increase over the TPI. To save even more money, don't bother with the Performer intake - the stock part isn't so poor as to warrant its replacement on a stock L98 longblock.

 

Wait, do you only have the L98 shortblock, and want to put the LG4 heads on it? If so, the heads really should be ported (bowl work, minimum) and 1.94" intake valves (and possibly 1.60" exhaust valves) should be installed.

 

i have a 89 iroc with the 350 tpi but the body is rusted beyond fixable so im just gonna take the l98 out of it and im getting a lg4 z28 and i wanted to put the intake and carb on the l98 to replace tpi. So my plan was to keep the stock heads from the 350 on there. Also just with stock lg4 top end ill gain 50hp? how much torque will i lose will it even be worth my time? I would just mod tpi but the parts cost to much and i always thought carb would make more power (improving ets mainly) Is there a good intake and carb i can put on there instead of stock lg4 crap?

 

is there any performance carb and intake for lg4 that is better then stock? And i see that the lg4 is computer controlled does that mean i would have to computer tune it if so its kind of a waste for me to go carb.

 

" Is there a good intake and carb i can put on there instead of stock lg4 crap?" Please do not insult my favorite form of induction.

You're putting the l98 long block into the LG4 body, right? Just put the lg4 manifold, carburetor, sensors and dist (if not 87) onto the L98 engine when it's installed and adjust your carb. No prom tuning but you will have to turn some wrenches and use a dwell meter and multi-meter. Upgrade your secondary rods hangers and go.

I see your lg4 is 87, should have same distributor so either would work. Save your spare these later HEI's are not as durable as the earlier ones, IMO.

 

sorry im learning do you have any part numbers for the parts you told me to get to upgrade the carb just directly swaping tpi to ccc will i see a gain?

 

For some info on upgrading the rods/hangers, try:

https://www.thirdgen.org/quadrajet

You will most likely see a gain. How much would depend on a lot of variables. Your new combo WILL be more easily tuneable to future upgrades and WILL support more power than the restrictive TPI intake (irregardless of tune). You may lose some of the "truck" torque down low the TPI is known for, lose a few mpg and suffer some cold weather driveability going from EFI to carb with choke. Of course these were things everyone lived with before fuel injection and the ccc-qjet spans the gap fairly well and much better than an aftermarket "performance" carb.

 

The Performer intake is slightly better than the stock part. Since you have the whole L98 engine, it will have the '87-later style intake mount bolt 72 degree angle on the center two bolts on each side. That makes the Performer slightly more expensive than the more "standard" '86-earlier version. You can go with the non-EGR version if emissions inspection isn't a factor (if you need to go through emissions inspection/testing, stick with the EGR).

As both naf and I are trying to say, the CCC q-jet is a very good street performance carb, so stop trying to figure out something better. Spend your money where it will actually yield some benefits. A dual snorkel air cleaner is needed to get the most out of the combo, and will provide better driveability than an open element. Either find a 3rd gen dual snorkel, or fabricate one (there's a link "Home Made Dual Snorkle" at the top of this page). That's really where you should be spending your money.

You should be able to get a pretty good price for your unused TPI equipment. The low-end torque can easily be made up with a higher stall torque converter, something in the 2200-2400 range. Another good place to spend some money.

Use the knock sensor and module from the L98, by the way.