Zink57

I own a 87 IROC with LB9. I am at the point where I am considering rebuilding the motor. I have seen a lot of useful posts on the board regarding different combos- L98 or LT1 cams and after market heads, intake manifold porting/upgrades, 1:6 ratio rockers so on and so forth.

My Question is.. with my IROC's current combo- 3:42 posi, 2500 RPM stall, Edlebrock intake and gutted air boxes-- the car seemed to increase a lot of performance even with the LB9 "Peanut Cam" with stock heads.... The 64,000 question is how much more perf should I expect by upgrading the CAM to a L98/LT1, springs and higher flowing heads (Trick Flow) with a custom chip?????? The reason for the question is because to add the aftermarket heads to the rebuild plan will increase the cost significantly as opposed to just cam and springs as upgrades when I rebuild... I am stuck in the CA so I have to deal with the SMOG **** so I am only interested in streetable daily driver that can pass the smog....

A lot of posts refer to the technical .. but don't mention how much of "seat of pants" improvement they get when they do the whole package....

Damon

The difference just in factory HP rating between the peanut cam 305 motors and the higher performance cammed 305s (that got the same cam as the L98) was never less than 25HP.

I've worked on plenty of them and below 3000 RPMs it doesn't feel much different. After that the bigger cammed 305 just walks away. And that's with no other changes. Add in the headers, better flowing intake, higher stall converter and (if it's in your budget) performance heads and it all tilts the tables further and further in favor of the bigger cam.

The chip tune matters, too. Not like the stock peanut cam chip can't run the motor any more, but you're leaving a lot on the table without a good tune.

And if I may make a suggestion- you'll be pushing the limits of the stock 305's 19 lb. injectors with all those mods. Changing the injector flow value in the chip to work with bigger 22 or 24 lb. injectors is very easy to do and it would be the first think you'd change in the chip tune. Plus, changing injectors is kind of a PITA on the TPI so why not do it at the same time you've got it all taken apart anyway?

Zink57

Damon
Thanks for the input.
I already have the 3:42 posi, 2500 stall, and intake mods-- with the peanut cam it runs a mid 14. I think you are right about the 22 lb injectors if I get the aftermarket heads with the intake mods and a custom chip.. it will run very well... The headers may be an issue in CA though...

Zink57

Question-
With an TPI LB9 rebuild with L98 cam, Vortec style 305 heads, 1:6 ratio springs and 22 lb injectors.. will the prom need to be recalibrated to accomodate the extra air flow/fuel of these upgrades? Will it work with the stock MAF sensor (1987 hot wire) style.

sofakingdom

iTrader: (1)

If you "rebuild" a 305, the SINGLE BEST mod you can do to it is to install a "bore kit", to enlarge the bores from 3.736" plus overbore, to 4.000" plus overbore. Cheeeeepest HP money can buy. Biggest bang for the buck, biggest increase in torque and HP, biggest best most greatest EVAH compared to anything you can do leaving the original bore in there. And best of all, it makes EVERY OTHER mod, work just that much better TOO. A total win-win-win situation.

Zink57

I have heard of a stroker kit but not a "overbore" kit..... Overboring a 305 will not leave the cylinder walls prone to weakness?

Damon

He means put a 350 in it.

Zink57

I think it all comes down to how much "extra" you really want. With the diff/stall/intake and exhaust work already performed.. the upgraded 305 LB9 should easily make the ride a very nice improvement over stock. Throwing a 350 in there would provide more.. tossing a 383 in there would give even more benefits.. I guess it's really a matter of how MUCH you want to go with. I am not looking for the fastest IROC on the road .. my motivation is just to make it a bit more "fun" to drive. If I wanted all out perf I would just go Alky, and a 3000 stall, and fuel pump mods on my TTA and blow 98% of the stuff on the street away.. but all out perf isn't my goal with Camaro...