Hello,

I would like to make some modifications to my 305 motor and this site is a great help. I know a lot of you guys have gone the route that I may be going and hopefully you can tell me if this combination will work or not. I have a 91 RS

Looking to get an edelbrock tbi manifold #3704
A camshaft from a vortec l31 or a 94-97 LT1 Z28
A stage 2 chip from tbichips.
Shorty headers and a complete 3" exhaust of course

I would like to maybe install roller rockers maybe 1.6 but not sure if the heads support rollers or what type will bolt right on.


Thanks for any advice.

Mark

 

Assuming your engine has the peanut cam, the L31 cam (same as the B/D body iron head LT1 cam) would be a reasonable upgrade; however, unless you already have one in your hands, I wouldn't bother. Go for the F or Y body LT1 cam; it's a better cam for a lighter vehicle.

No input from me on the Edel TBI manifold; I don't know if it's any better than stock.

I'd pass on anything that sounds like "stage X" chip. You really need a custom chip, preferably dialed in with a dyno tune, when you swap cams.

Exhaust: yes, your plan is good.

Rockers: Hopefully somebody familiar with that year TBI heads will chime in, since I don't know if your rockers are guided by the pushrods against slots in the heads or if they're S/A (self-aligning) rockers that guide on the valve stem. Regardless, yes, you can run full roller rockers; just have to select the right kind - either S/A or non-S/A.
1.6 ratio may or may not work, depending if there is enough pushrod clearance on the stud side of the hole/slot in the head (1.6 rockers move the pushrod closer to the rocker stud).

 

As far as I know, the only rockers that are self aligning from GM came on the Vortec motors.

For a cam, look at a Lunati 60102, 60103 or equivilent from Comp/Crane/Isky.

Don't do the Chip, waste of money.

Do a search on the boards here for TBI upgrades, there are several that will benefit you but your exhaust upgrade is one of the best.

Look at Hooker 2055 or Dyno Don's headers for that upgrade.

 

Thanks 86LG4Bird & Ozz1967. TBIchips.com makes a chip which was programmed to use the LT1 cam that is why I was going to go with a chip. I read that a lot of chips are a waste of money though. The first step will be exhaust for sure.

With all the reading and information here its hard not to want to build a 350 or LS1 motor

I saw edelbrock makes an aluminum head for the 305 also but your looking about $500 per head..don't want to dump that much into an old motor..

 

If you're going to buy new heads, you want the World S/R Torquer 305 heads.

Or, you can look up MW66NOVA on the web site here, he modded his 305 heads for his screaming 305 to be essentially the same as the ones from World but, unless you're doing the work yourself, you're going to be out about as much money as buying the new ones.

I was going to simply rebuild my 305 but was talked into doing the 350 since I had to pull the motor anyway. Made sense for me and I picked up 120 RWhp and 100ft-lb of torque on the Dyno for he same money as the rebuild would have otherwise cost me.

 

from what i understand heads would be a huge upgrade! If you wanted to go a cheaper route maybe some vortec heads. Also with cam and heads your fuel system is going to have a hard time keeping up. I read that the stuck fp will run out around 200hp