I have a 92 RS heritage edition with a 305tbi, it's just not fast enough for me. I would like to swap out the motor. Would it be cheaper if I stuck with a TBI motor than swapping to a MFI? I would really like to drop a vortec in my car, if I go from TBI to MFI what would I need ? I can't find a clear answer online, thanks

 

Hello,

Well, there's a multitude of options available to go from TBI or carburetor to MPFI, however that won't make the difference in power you're looking for. I think, the cheapest, most rewarding way to inject good power to your car is to swap the cylinder heads for a set of vortecs. They run circles around the stockers and will give you 30-40 extra hp out of the box (assuming an ECU retune to compensate for the extra airflow).

You will need a dedicated vortec intake. There's a Vortec TBI intake, however it's expensive, only buy if planning to keep the TBI. Another option is to get a dual-plane intake for carbureted applications, install a TBI adapter plate and you're good to go. ECU retune is still required.

When the short-block gives up, then you'll only need to invest in a new 350 short-block, the heads will bolt up and will gain even more hp and torque.

Hope this helps.

 

Thank you, what if I swap to a LB9 305, then what would I have to change?

 

Well, I don't have the LB9 specs at hand but again, installing Vortec heads represents the best bang for the buck even if you don't plan to eventually upgrade to a 350 short-block. The L-31 Vortec heads are the best flowing and more efficient combustion-chamber design ever produced for the Gen-1 small-block.

No other 305 or 350 (with stock heads) will give you more. If going the Vortec route install them as-is, right out of the box, just blow 'em with compressed air and install using Fel-Pro's steel shim gasket (0.015 compressed thickness) to get the highest compression possible. Don't mess with the valve seat and don't try to port them, it's not necessary, right out of the box the Vortecs outflow many "race" heads.

Even if you upgrade to a small street cam the gains will be huge and still idle
smooth as glass.

 

When I get the heads is it best to get the vortec tbi intake? I seen it was only $4-$500 which isn't bad. I plan on paying around the same for a cam

 

Well, if money is not a problem get the Vortec TBI intake, that way everything will bolt up, coil, TBI, harness grounds, etc. and it will look factory stock, also you'll able to re-use the current valve covers and bracketry.

Keep in mind this: LS motors are what they are thanks not to the MPFI sequential injection that fuels them but to the massive airflow of their cylinder heads. The same holds true to today's Dodge HEMI. The stock cylinder heads outflow every LA 360 c.i. race head.

Then of course, comes their excellent EFI systems, but just as a complement. Even in carbureted form, LS motors produce huge power. Take for example a bone-stock 5.3L out from any truck or SUV, install headers a small cam and some basic tuning and you're at the 450-500HP mark. All thanks to their cylinder heads. Airflow is the name of the game.

As race engine builder Joe Sherman says: "Every dollar spent in the heads will be rewarded two to three times more than if it was spent in the short-block"

...or as Chevy engines builder John Lingenfelter once said: "If it comes down to a choice between a roller-cam or better heads, buy the heads"

Happy wrenching!

 

do they make those heads in aluminum ? I only see cast iron