Z2EIGHT

I'm looking for a little bit more power and I was wondering if there is a nice cam out there or some good cheap heads I could throw on and have a little more aggressive motor? I want something that is an easy upgrade and no custom work.

I want lots of grunt.

Vortec heads made for a 305, good or bad? I want to spend less than $1k if that is possible.

Thanks

aweTastic

Well depending on what you do with heads is what you do with the cam...
A cam isnt necessarily an easy upgrade you need to pull your radiator lift you motor a bit and pull your water pump and timing off and etc. If you want a better cam and you dont change your heads then an LT1 cam is your best bet cuz its your highest lift possible on stock heads and doesnt require a tune... if you do change your heads and get new springs you can go bigger lift but will probably need a tune so it depends on how much grunt you want if you decide to go bigger then LT1 =P

as far as vortec heads go... i personally havent used them =/

Hope this helps

Nelz

Good Heads + weak cam is better than Good Cam + weak heads.

Either port your stock heads with a 3 or 5 angle valve grind and back cut your valves 30 degrees (This is the cheapest way. But you can price this out to see for sure.) or go with Vortec heads.

I don't think the 305 Vortec heads are as good as the 350 L31 castings. The springs on the L31 have enough lift for the stock peanut cam. You may (read probably will) have to go with a thinner steel gasket like 0.015" to keep compression up with them or have them milled. But then you run into buying a $400 intake manifold from Scoggin dickey.

Here are some links in regards to the 305 vortecs:
http://www.hotrodders.com/forum/1255...ds-108643.html


From the sounds of it, if you just want to do it on the cheap, port your heads. Othewise, it'll cost you about $600-$900 for a pair of Vortec heads from Scoggin Dickey (the price on the website if for ONE head), and another $400 for an intake manifold. And if you ever do decide to change the cam, you'll spend another $250 on beehive springs and/or the maching work to get regular springs to drop in with the correct locks and retainers.

Z2EIGHT

Will a LT1 cam make any gains, noticeable at all? Any exhaust difference?

flaming-ford

iTrader: (7)

not a noticable difference in exhaust note as for a noticable change in power definetly probably 15 to 20 hp throughout the range. big gains in your upper and mid range and probably no real loss on a low end. that being just with the camshaft swap.

As for heads everything out there fore a 305 head is excessively expensive, or requires add ons like a specialty header to perform best, or a specialty vortec based manifold. the only direct bolt on head thats a litte better than factory but not worth the money, is world products sr toruqer 305 head or trick flow heads which the price is just insane on. flow is only minimalistically better too.. head work along with bigger rockers can be a 30hp mod easily as well.

personally if you want a big jump in power i would reccomend pulling your old heads and doing very minor cleanup porting +.050 locks and retainers. then install a lt1 cam and run 1.6 ratio rocker arms. that would make for a 250hp motor.

you can often find redone 305 heads from board members for a fraction of the machine work price as well so keep an eye out.

Z2EIGHT

Thanks for the input, I'll have to keep my eye out for a LT1 cam, anything I should know about them or they all the same?

1MeanZ

iTrader: (9)

Do you have any data to back this up? He has a 92 Z28. All the later cars like that got the L98 cam, which by the way is nearly identical to the LT1 cam. The LT1 cam has a tad more lift and thats it. There is no way in the world you'll ever notice a difference between a stock L98 cam and an LT1 cam. The LT1 cam is a great upgrade for the TBI guys or the peanut cammed TPI guys but thats it.

Z2eight, what are your power goals? How much power do you want the car to have? If you haven't done it already, headers and exhaust are the first things to do. Then if you have to pass SMOG, port your stock heads, intake and go with a mild cam, something around 208-212 duration at .050 lift. IF you don't need to pass SMOG go with 87-91 L98 Corvette heads or GM ZZ4 heads.

flaming-ford

iTrader: (7)

i though all the automatic cars got the peanut cam it says in his sig he has a 305........ i just assumed it was same as you assumed he still had the original 350 so i guess we are both wrong... scratches head....... lol doh.

the l98 cam is still a bit smaller than a lt1 cam just not much.

but no if thats true and the 305 was from a late model then maybe "mean" is correct i thought the 305 tpi motors with autos were all peanut cammed shows what i know.

anyways i he is correct then you'd be lucky to see 5 hp difference in the camshaft swap.

Z2EIGHT

My power goals are 250-275. They were originally 300 but that seems unrealistic with my budget.

Let's just say 250hp, I have long tube headers, 3in Y, cat, and a flowmaster catback. K&N filters, MSD GM Blaster And MSD Super Conductors, and maybe a few other things...not much, I just want some more pep.

1MeanZ

iTrader: (9)

You make no sense. If you do a search, you'll find that all 91-92 TPI cars have the same cam regardless of 305 or 350, or 5 speed or automatic, they all got the same cam, it's been proven.

1MeanZ

iTrader: (9)

All I had done to mine was the corvette L98 heads, cam, headers, ported intake, and cat back exhaust. The car had very close to 300hp give or take a few. That was even on the stock tune.

Z2EIGHT

Won't you lose compression with the L98 heads? I have a 305.

I don't know what compression really is so I'm confused. I also have an automatic so I'm factoring drivetrain loss.

navyCM

iTrader: (3)

why not just get a cam the biggest cam you can use w/ your stock tune and some 1.6 rr's? that should keep you under a $1k. from what you mention you already have a cam and 1.6s should get you what you want if not more.

or see if you can find a set of 081 heads used w/ port work done to them already. there pretty easy to find on here and ebay.

it really depends how much work you want to do to upgrade.

1MeanZ

iTrader: (9)

No the aluminum Corvette L98 heads have 58cc combustion chambers, the same size as your 305 heads do. You will not lose compression by swapping to these particular heads.

Compression is commonly discussed as a ratio. Your stock compression ratio is 9.5:1. That means that the volume or air space of the cylinder when the piston is all the way down (bottom dead center) is 9.5 times the volume of the cylinder when the piston is all the way up (top dead center)

1MeanZ

iTrader: (9)

This is false. There is no cam that is enough larger than stock to provide a power increase that will still be optimal with the stock tune, especially on a speed density car.

Z2EIGHT

I'm now confused. I was always told if I switch to L98 I would lose compression, but now you guys are telling me that these Aluminum Corvette heads will keep my compression the same? Compression is good I'm assuming, but what will these aluminum heads do my 305 iron heads can't besides save weight?

TPI

Because the aluminum 'vette heads have the same size combustion chambers
as the 081/416 305 head, you will not lose compression. If you were to track
down a set of iron L98 350 heads, you would find that they are 64cc.

The aluminum heads are less prone to detonation, runs cooler and can
flow pretty darn good.. If I had some, id rip my 081's off right now.

1MeanZ

iTrader: (9)

The vette heads flow very well for how small the ports are, which means the air is moving at a high velocity, which is good for a TPI car. They also have fantastic exhaust ports for stock heads. Even untouched, they are a great power increase on a 305. I'd hazard that they may be worth 30hp or more over the stock heads. When I swapped mine I went from a 14.8 to a 13.7 in the quarter mile. I also did a 5speed swap at the same time, and I mildly ported my heads before I installed them.