Hey guys,
Got my 305 specs in sig, and when originally did the build I ordered a roller cam .480/.488 and 212/214 duration @ .50, after 3 miles spun rod bearing so yanked motor and when i did i decided i wanted a bigger cam, well called the summits guys gave them my set up and the cam they sold me was a comp cam .510/.520 lift and 232/236 duration @ .50.
Well i ran the cam all last summer an car runs good and sounds great BUT seems like something in the mid range is missing, the more i got to thinking i realized how much duration this cam has for such a small cube engine with stock heads, the other 305 builds i've seen used cams with much less duration. my question is would i be better off throwing in the smaller cam with less duration? consider my mostly stock l03 heads, ( milled, slight port work and 1.94 valves)
Also thinking about the RPM air gap intake, from what i herd great intake, good for my set up?
Thanks guys.

 

Yes, it would run much better with the smaller cam, at least anywhere below 5000 rpm.
I run a 228 HR cam in the LT1 (350 ci), and the torque peak is 4600 rpm. At 305 cubes, I'm not surprised midrange is lacking with that 232 cam!

 

thanks for the reply,
whne im at the track i turn it 5500 although i few guys on this site told me to try turning 6, i have let it touch that high on streets and it seemed to still pull good.

 

Sure that cam will want to turn 6000, but your heads are falling off long before then.
It's a mismatched combo. Put the smaller cam in and you'll be faster at the track.

 

i know the heads are my liminting factor right know, what would you suggest to do about heads?
Vortec 059?

 

If you go vortec add 1.6 exhaust valves and clean them up a bit to spin to 6k

 

I'm also alittle unsure if the 305 vortecs came with 1.94s or not, it was my understanding that they did although someone told me the did not? still the 1.84's like 305 tbi heads?
Also, can i make these l03 heads flow enough for my set up or would i just be wasting my time with tbi heads?

 

Right forgot they were the 305 heads. They are 1.84, 1.5 IIRC.

I know the 1.94 version don't really benefit from 2.02 valves but they do very much enjoy 1.6 exhaust valves.

 

So should i stick with my l03 heads and just hog the exhaust side for 1.6 valves?
Yea I dont think you can run 2.02 on 305s small bore anyways. I did bore out intake side and have 1.94 stainless z28 valves now and some pretty minor port/polish work.

 

059s come out of the box with 1.84/1.50s, but really love 1.94/1.60s with a touch of bowl work and the right valve job angles. That being said they would easily add a substantial amount of power over 5,000 rpm, especially with that cam. However for the compression ratio and small cubes your midrange will certainly lag with that much cam. If you switch to vortecs with 1.94/1.60s I would drop back to something around 218* on a tighter LSA. 218/226 @ .050, .500/.520, 108* LSA, 106* ICL. If you stick with 1.84/1.50 valves I would tighten the LSA 2* more to 106* LSA and advance to 104* ICL.

I would drop back to something like this......Running a 1.6:1 rocker

http://www.summitracing.com/parts/hr...make/chevrolet

 

Are the old 916 heads any better than what he has...the ones off the HO cars? Just curious...

 

I have an 89 with a 5.7 l . I have a .502 / .510 " lift cam .110 sep. I would like to keep the stock L98 heads. But i know i cannot use the stock springs . Any thoughts on what size spring i should go with ? I would like to not have to have any work done to the heads .

 

thank you fast355 for the great info.
As far as compression ratio, I have kinda been in the mist of collecting some parts for a stroker kit, with that being said i would definitely be putting it some hyp pistons, maybe forged, but something around +5-+7 dome, so with that and my .015 shim i should be looking around 10.4:1 or so vs my current 9.4:1. So im assuiming that would help with my mid range. Now with that said, assuming i pick up a set of vortecs is the cam you put in link the cam youd stick with?
THanks again guys for the replys, hard to find anyone around here that'll give you the time of day when you say ¨305¨ lol