85 lg4 build
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
85 lg4 build
85 sport coupe and done the exhaust so following the building procedures it is cam next. so COMP Cams K12-234-2 right? sound ok? in the case that this is ok and i get this setup will i need machine work prob not right? however new pushrods? or no? cause i dont know what size they are and they have many different sizes for sale. how about it, can anybody lead me in the right direstion
Joined: Mar 2000
Posts: 43,187
Likes: 45
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
No machine work required.
You need the "longer" SBC pushrods.
You need the "longer" SBC pushrods.
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: 85 lg4 build
That cam, despite the 256-degree advertised intake duration, is on lhe large side for an LG4. You'll lose enough idle vacuum for your computer to notice. I suggest you'll still find a noticeable improvement by dropping down to a 12-388-4
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
i looked up that cam 12-388-4 and i dont know thats why im asking but it says for tbi and tpi motors only is that a big deal cause i have a stock q-jet. also what exactly would be the longer push rods cause there seems to be like four sizes for sbc rods? one last thing, if i get the smaller cam it doesnt come with lifters and springs so how do i know which ones to buy?
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
sorry guys and gals im a amazing mechanic when it comes to putting together and taking apart kits but understanding how it works with different parts and putting matching sets together is kickin my tail
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: 85 lg4 build
The TBI/TPI reference is due to vacuum, and your computer for the Q-J is looking for vacuum the same as those are. If you had a non-computer engine, you would be better off with a 110 lobe sep.
Using the 388 cam, you can use Comp's high energy lifters and 980-16 springs.
Using the 388 cam, you can use Comp's high energy lifters and 980-16 springs.
Trending Topics
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
so really in order to reach the full potential of the trusty old 305 i am gonna have to replace the distributor and intake and carb so i can run a non cc engine? because if i keep the q-jet that everyone talked me into buying for almost 400 dollars remaned, then i am basicaly restricting my engine to half of its potential so that i can run a cc carb. is that right? cause i dont want a 350 thats to much money brand new and far to much work from a junk yard. dont have that kind of time to devote to this.
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
however my origional choice the K12-234-2 is basically going to get me everything that 305 can get me with a new distrib and intake carb combo.....right?
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: 85 lg4 build
going up to your cam, might net you another 10 horses and another 10 ft-lbs, plus a meaner-sounding idle. But staying computer-controlled is still worth that loss, because driveability means so much more. Plus better gas mileage, and the potential for longer engine life. The computer-controlled carb and distributor can support an awful lot more power than your 305 will make with either cam, but you do have to accomodate it. If you want the cam you chose, and the computer controls, you may need to do some re-tuning, probably by means of a custom chip.
But the bigger cam isn't your friend if you're still running 2.73:1 rear gears, and/or the stock exhaust system. And when doing a cam swap is the perfect time to upgrade to an aftermarket intake manifold.
But the bigger cam isn't your friend if you're still running 2.73:1 rear gears, and/or the stock exhaust system. And when doing a cam swap is the perfect time to upgrade to an aftermarket intake manifold.
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
ok so against all suggestions.... i put in the K12-234-2 kit and an accel vacume and mechanical dist and an edlebrock performer intake holly 600 cfm carb with elec choke.
Thread Starter
Member
Joined: Jul 2008
Posts: 144
Likes: 0
From: NC USA
Car: 1985 Chevy Camaro
Engine: 305
Transmission: 700R4
Axle/Gears: 3.08
Re: 85 lg4 build
so... i have put everything together and it seems fine.... took it to the track last night ran horrible and for some reason from a stop i cannot mash the gas or it trys to die.
have checked timing with vacume advance unpluged and capped it is about 8* at idle wich i thought was ok.
valve lash when i do the valve lash like the manual says my motor sounds like a drag car and the motor shakes considerably more than if i back all the rocker nuts off about a quarter turn more than the adjustment the manual says to make.
should it sound wicked with this cam and should it shake or should it run smooth and sound ok
have checked timing with vacume advance unpluged and capped it is about 8* at idle wich i thought was ok.
valve lash when i do the valve lash like the manual says my motor sounds like a drag car and the motor shakes considerably more than if i back all the rocker nuts off about a quarter turn more than the adjustment the manual says to make.
should it sound wicked with this cam and should it shake or should it run smooth and sound ok
Thread
Thread Starter
Forum
Replies
Last Post






