Yeah I know, let me explain.

Right now I'm fairly happy with the performance that I get from my 305. Around here there are not a whole lot of fast cars. I can beat most everything except the newer Chevy trucks Rams, ect. I need some help with the selection of parts for my 305. I'm gonna stick a little money into it so the car will be quick while I spend the next year saving up/ building a awsome 350. Now on to my questions.

Cylinder Heads
There are a few choices, (World Torquer(sp), Vortec, Ect)

Is it possible to make the sucky L03 heads actually flow? Port & Polish? I was also told the LB9 heads are better is this true?

TBI

I'm keeping TBI- plan on doing the mods (or whats that guy's name on here that does the mods?) and adding 350 injectors. Or is changing over to a carb worth it?

Adding a 14" spacer.

Camshaft / Springs / Rockers

I know very little about camshafts. I know I want to have a mildly loppy cam. Any suggestions on Springs / Rockers / Cam.

Intake

What intake should I go with?


My target is around 300+ if possible. This will be a daily driver and stoplight racing (I need torque). My exhaust is all good and I have a set of headers waiting to be installed. The car is gettin' posi with 3:43's. B&M shift kit, vette servo. What size converter do you recomend? I will be adding a 100hp shot later on also.

Thanks

 

As far as heads and intake are concerned, if I were in your shoes and wanted some good power now out of the 305 and plan on moving up to a 350 shortly, I'd get the Vortec 350 heads and a matching vortec intake either carb intake with a TBI adapter, or I think they make a vortec TBI specific intake now. Some mill down the vortecs if they're using them on a 305 but I'd keep them how they are with the 64cc chambers you won't lose that much compression and then when you swap the 350 just use the same heads and intake. This would end up costing you less in the end and vortecs are very good heads to use 305 or 350.

 

Yea, I have also thought of this. It would save me a bunch of money, but I was told that the compression would be approx. 7.5:1 this is very low. So I would have to mill them or buy new pistions. Which is cheaper?

 

About 110 bucks for a set of new speed pro hypereutectic pistions. plus rings & berings and all the work involved with putting them in- I really don't wanna pull the engine.

But i also don't wanna spend another 400 bucks on another set of vortec heads.

 

I really didn't think it would drop as low as 7.5:1 since its at 9.3:1 now with 58cc. I know there's some calculation to figure out compression loss or least a guess at it, maybe someone will help us out with that?

 

going from 58cc to 64cc drops from about 9.3:1 to 8.7:1

 

Depending on the thickness of your head gasket you shouldn't drop bellow 8.6 to 1 cr. If you use a thin head gasket you might even be able to keep it close to a 9 to1 cr.

Steve

 

Forget about heads and cam right now. You need to do the ultimate TBI mods, open air element, and a cat back to go with those headers. After that your car will feel and sound totaly different and will make you smile. Worry about heads and cam later. Once money comes around do the gears and posi which are 3.42's not 3.43's and add some simple suspension upgrades to plant some of that car to the road. No need for hyperutectic or forged pistons now or frankly ever on a 305. If you stay N/A you can get away with cast pistons.

 

I don't think a 14" spacer will fit

 

id go with slp 1 3/4 headers.

 

that would be me who does the ultimate tbi mods.

 

ShiftyCapone

Like I said my exhaust (cat-back) is taken care of. I have an open air 14 X 3 element like my sig says.

The only reason I brought up the part about the pistions would be if I had to put ones in that have more compression.

To all- The guy who wrote the 7.5:1 compression was way wrong. So now I got the Heads taken care of. They will be vortec L31's. The intake will be a Performer RPM Air-Gap for Vortec heads. Any suggestions with a cam?

 

if i were you, for the cam, i would call a couple of manufactures, and see what they recomend.

but, i will get into this....

the Comp XR264-HR12 is a nice cam, but the stock vortecs would need to be machined for the lift on it. and it might be too big for the lower compresion you will be running.

i am not at home right now to plug some numbers into my DCR calculator, i can do that this evening, see how large you can get away with on that compression.

i think you would be happier if you get them machined to take the lift, and run a cam with close to .500 lift. to get the 300hp goal of yours, you are going to need to run a fairly aggressive cam, but with your low compression i don't think you can get as big and 'i' would like to run for that kind of power goal. you may need to run a cam in the 204-206 intake range to keep the cyl pressure up, if so, the ZZ4 cam might be a nice choice.

like i said give me some time to play around with some numbers, and i will get back to you.

 

tyty49

I reread your sig and see that you do have those things, woops. Anyways Dewey316 is right about cam selection. A lot of guys go with a LT1 or LT4 cam and see nice results. I am friedns with a member on this board who has milled vortec heads and an LT1 cam and tuning and his car flies for a 305. He will be switching to a slightly bigger cam (not sure on duration but .499 lift). Make sure that you upgrade your fuel delivery as well or you will not be able to feed anything bigger than the LT1 cam.