1991 rs 305 automatic with 125,000miles. Transgo shift kit, 2800 stall, performer rpm intake, switched tbi to carb, open element filter, world products torquer r/t heads, headers, 3 inch exhaust no cat to flowmasters, lt-1 cam, 4,10 gears, and subframe connectors???? what do u think it would run in the 1/4 mile??? thanks alot. Do you think i would need nitto's???

 

i cant really comment on how fast you'd be, but as for the nitto's, any car will benefit from drag radials over street tires.

 

If you are doing a buildup from scratch:

go with a set of vortec heads instead of the world products
put a larger camshaft in it than the LT1 cam

I wouldnt be surprised if you got it into the 14's with those mods.

 

i will guess high 14s also.......converter and tires will help a great deal

 

What cam would you guys recommend?? How much do vortech heads cost?? Wow i was hoping for mid to low 14's i guess the 305's a pretty weak.

 

Vortec (no h) heads will cost significantly less than the World Products cylinder heads. I think they are right around $240 per cylinder head. I would also have them shaved down (assuming that you have sufficient piston to valve and piston to head clearances) to 57'ish cc to keep your compression up. The only thing to keep in mind is that you need to buy Performer RPM for vortec cylinder heads.

As for a camshaft, if you are on a budget I would go with something like the comp cams XE262 hydraulic flat tappet camshaft.

 

what if i have vortecs and the cam you suggested what i run??? THANKS ALOT for all the help trying to find out how fast (or slow) i can make this car before i buy it.

 

Probably well into the 14's. It really depends on the shape of the bottom end as well.

 

Is 125,000 alot for a 305 bottom end and is that alot of stock tranny?? I think that the guy selling this car took car of it a little better then most people. But then i go on the tbi board and see stock 305 bottom ends going close to 200,000 miles and they say that they beat on them alot. If i got this car would changing it to carb help up preformance alittle? b/c the tbi is prob out of adjustment. The main reason i want carb is b/c i dont want to burn a chip just b/c i got exhaust or open element filter. But on the on other side it will be me everyday driver. Thanks for all the help. Would like to get a 350 tpi but i cant afford it!

 

Not by the time you get time set up properly to handle more than .420" (some will say .440", others .460", or .480") lift, shave them for 305-size 58cc chambers, and buy the required Vortec-specific intake manifold (which will also have to be shaved).

 

If you have ever worked on a vortec cylinder head you will know that is a myth. I run just under .500 lift with $50.00 into my vortec heads. A set of K-motion valvesprings, unbrella style seals and + .050 installed height retainers is all it takes. It cost me $40 to have my heads shaved. If you have seen the flow # difference between S/R torquers and vortec heads I think it is definately worth it.

 

And why would the intake manifold need to be shaved? I run a victor for vortecs intake with a 57cc combustion chamber with no problems whatsoever. A lot of people dont know that vortec cylinder heads CC around 61-62cc out of the box, mine came in at just under 62 cc.

 

Your experience seems to verify the factory production variability that is so much fun to deal with. Not knowing what your chamber size will be, differences in valve guide height so you may be limited to .420" lift but may get almost .5, etc.

If you take more than .02" off the heads, you should shave the intake to match.

Home-ported Worlds will support most any 305 flow needs.

But, if there was only one path to a destination, it'd be pretty boring, right? If the heads will someday go on a 350, Vortecs might be justifiable. Personally, I need to pass emissions inspection/testing, so they just aren't a very good choice for me. Since approximately 50% of the people who frequent this board have some sort of emissions to deal with, it's a good idea to keep that in mind. (Admittedly, going TBI -> carb would tend to indicate that isn't on the originator's mind.)

 

I dont think it is a variation in guide height, i think it is a variation in what feel is acceptable for retainer to guide clearance. To give you an idea, the 350HO crate engine (which is what I own) comes with a camshaft that has .435/.460" lift and unmodified vortec cylinder heads.

 

I have to pass emmissions will the vortechs pass???

 

Depends upon what you have to "pass".

Strict visual inspection - no.

Dyno sniffer that includes NOx - maybe, more likely if you do an external passage EGR set-up.

Simple sniffer w/o NOx, no under-hood visual inspection - probably.