macmatt

I have an LO3 305 in my car and have decided to stick with it for now since it is in good shape. However I wanted to do some upgrades to give it a little more kick. I know most people would say to just get a 350 and be done with it but I wanted to be different and stick with what I got. My goal is to get 1hp per cubic inch out of my 305, do it with only bolt ons, keep the compression ratio at stock or a little above (9.5:1 max), and keep the TBI setup(I just don't have the patience for an injection swap right now) Here is what I've come up with so far...

Vortec 305 heads
Camshaft for a corvette from 1991 (Same year as my car)
Headers w/high flow cat and flowmaster muffler
Bump the exhaust up to 2.5inches
Roller rockers w/1.6 ratio
Double roller timing set

Thoughts?

Thanks guys!

UnderCover89TBI

iTrader: (25)

power is made through heads, cam, and compression. at least run an lt1 cam. you'll need a way to tune the engine. something like dynamicefi.com. do not think all that will get you to your goal but will be respectable.

pound

iTrader: (7)

I think you should be looking for a larger cam if you want to hit 1 HP per cube N/A.

Might as well get a 3 inch exhaust here. This way once you give up on the 305 you won't have to buy exhaust again.

I'd pass on this and get a quality single roller timing set.

As mentioned by UnderCover89TBI you most certainly are going to need some way to do custom tuning once all the parts are swapped.

macmatt

Thanks for the suggestions guys.

On the cam here is what I'm looking at...



Cam 1 is my stock cam (or so I'm told)
Cam 2 is the Corvette cam (which is also supposed to be the same cam as what's in the GTA's and Z28's with 350's)

Should I still go bigger? I was hoping to not have to do any major computer modding but will if it will help meet my goal.

UnderCover89TBI

iTrader: (25)

well your going to have to get the egr deleted out of your computer regardless. computer is the brain for efi.

that cam is small still. you can use it but you wont meet your goal IMO

Teal88

If you get those 059 (5.0l) Vortec heads they should be able to handle up around .470 lift..maybe a bit more. I picked up a set of marine 059's for $250 for both and I should've had the valve stems upgraded before installing them.

Don't forget that you'll have to buy the GMPP TBI Vortec-style intake (or votec-head compatible intake) as the intake manifold bolt pattern is different from pre-vortec engines.

robertfrank

iTrader: (27)

That cam is way too small in my opinion, the absolute lowest I would go is a ZZ4 cam. Believe me you'll want to go bigger once you get that cam in. Truthfully just start on the rest of the car before you start digging into the motor. Gears, FULL exhaust (headers back) suspension will make the car much more fun to drive before you'll ever have to worry about tuning just yet. for example you can start like this....

Starting from the REAR and working your way forward.
Get a rear end from either a V6 Fbody or rebuild yours with the right gear set 3:42's are good with an auto
Redo the suspension and stiffen up the body
Headers with full 3 inch all the way back, muffler choice is up to you but I really recommend the Hooker Aerochamber
Beef up the brakes, work on the WHOA before the GO
Get a good stall and a good shift kit, Trango and Edge are top notch. check out www700r4l60e.com

and THEN start tuning to get a handle on it. You can do alot to the car to make it much more fun to drive before you even have to go near the motor.

irishhockey34

iTrader: (12)

You definatley want more cam than the corevette cam you picked out if you want to hit your goal with that 305. But as stated above, full exhaust, intake, rear end/gears, then get into motor work

UnderCover89TBI

iTrader: (25)

you deffinately want to take Robert's advice his car is top notch

SKELITOR117

iTrader: (3)

Yep. This is what I'm doing. I just shelled out some dough for an LT1 rear disc brake set up and a megashifter (woah and go). Those two items are going to make the car allot more fun to drive. I've invested a little into the go as well. So far all I've got is some Nitto Nt555 285/40-17s (back) & some Continental Extreme Contact 225/50-17s (front), then a 2 1/2" Dynomax super turbo cat back, then a rebuilt 700R4 with a shift kit, and then a Hypertech chip and 180* stat up front. I'll be working on an air cleaner mod soon.

robertfrank

iTrader: (27)

there, fixed it for you lol. Go with a 3 inch man, you'll be much happier. Too bad you don't have an 88 Camaro, I have a "stage 1" TBIchips chip that would work a little better than the hypercrap garbage I'd sell too you for 20 bucks with shipping.

SKELITOR117

iTrader: (3)

I was going to get that system but I was 17 and unemployed. I only got the dino max 2 1/2 because the old system was rotted out and everyone I've talked to with this muffler style LOVED the sound (and I have to admit it does have a good sound). Plus Dinomax had a $90 rebate and the site I bought it from had an aditional $10 coupon code and free shipping. 110 bucks shipped to my door. I'll swap to a three inch system later when I have the dough.

I like the Hyperchip. Def more umf now.

Ron U.S.M.C.

Gears,posi. Gears,posi. Gears,posi.

NagleMac

iTrader: (1)

Youll definetly be happy with a gear swap, full exhaust, and a good air intake, also im not sure what the stock compression is but im assuming if its as terrible as EVERYTHING else on a 305, thatll be something you wanna change... by the way, long time no talk TBI guys, ive been busy in the engine swap boards, putting in a carb'd 383

UnderCover89TBI

iTrader: (25)

that hypertech chip worked good for what it is. Deffinately better options out there.