Hello all. Trying to see if anyone has experience with putting 1.6 rocker arms on a 91 roller cam 305 tbi. Getting cheap stamped ones from summit, stock style besides the ratio of course. Don’t care about hp or torque gains, just seeing as they’re the same price as 1.5s I’d rather save the money by getting them now and using them on my 400 sbc later. Only question is, with a edelbrock performer eps intake, will my ecm **** the bed or will this be fine for the time being, thanks.

 

The rockers need to be self-aligning for the L03. They do make stamped steel self aligning 1.6s, I havr used them and they do work well on completely stock engines especially the Vortec 305/350s and LT1s that benifit the most from added lift and duration under the curve. Most aftermarket heads do not use self-aligning rockers nor do factory 400 heads.

Intake manifold is pretty far down the list of what is holding back a L03 power wise. The EPS does not have the right bolt pattern and it will take a substantial amount of work to adapt it in place of a TBI manifold. You also need a chip with the EGR deleted and more acceleration enrichment fuel for the larger plenum volume. I ran a RPM with a 2" bore marine TBI and matching 2" tall 2" bore TBI to 4150 adapter on a stock TBI 350 HD long block long ago and it ran very well but it did take some tuning to dial it in so that it actually added power over a 3704 manifold with 2" bores and an open center spacer. I only put the 3704 manifold on that engine at the time because the coolant ports were rotted away on the stock aluminum manifold. Back in 2005ish a 3704 manifold was under $200 new though and a local machine shop bored it to 2" for like $50. If you do swap to an EPS and have a 700r4 the TV cable length and geometry is critical. I used an aftermarket bracket that bolts to the 4150 bolt pattern intended to be used with a Holley carb.

 

Granted it is on a different setup now with a TH400, this is the bracket I ran on the RPM/Marine TBI adapter/Marine TBI unit setup. Pulled it out of a bin of spare TBI parts I have laying around the shop to use for this setup. The cruise control on this one is a cut-down stock GM setup and the throttle cable bracket is a universal 4150 style. It comes with smaller brackets that bolt on for both the cruise control cable when remote mounted like a F-car and TV cables.

 

I am aware of the shortcomings of the lo3. I am aware of differences between the edelbrock and stock intake manifold, the machine work has already been done. I am aware of the egr valve situation it has been taken care of. I am aware that the 400 and 305 do not have self aligning rockers, as I said, they will be oe in every way except the ratio, meaning they will be stamped. I am aware of the tv cable differences and have a bracket to match. I am aware that I am not building a race car, that’s for later. I already know the car runs with the intake, I’m doing head work and need new rocker arms. Will the car run with 1.6 rockers without a tune. Not do wheelies, not do 0-60 in below 5 seconds, just simply will it run and not blow the **** up until I can put a carb on it. Thanks.

 

Are you sure about that? The 400 won't. The 305 might.

First Guess: The computer won't know the difference between 1.5 and 1.6 rockers.

I have 1.6 rockers on my K1500 5.7L, on top of aluminum aftermarket heads, and an aftermarket intake manifold. I'm not smart enough to tune a computer, so aside from jacking-up the initial timing, and adding some fuel pressure the "tune" is dead-stock. Not as much power as I'd hoped-for, and there's a mildly-annoying hesitation as the engine warms-up--not there when cold, gone at operating temperature, but present during warm-up.

Installing the carb is probably a mistake if you're able to tune the computer.