How does this really mild 305 build sound?

[Wade]

I've got a tbi 305, it's a goodwrench crate motor with under 40,000 miles. I want to hop it up just a little bit. My plan is a set of bone stock 305 vortec heads, a summit brand cam with .278,.288 duration and .421,.444 lift. I plan to reuse the stock pushrods off my 305, and the rockers. I will either use stock springs off the vortec heads or off my current heads, whichever are in better shape. I've never put an engine together, so I'm wondering if anyone with some experience has any input on the combination. Thanks!

Edit: it is in a firebird with a T5 that is only rated at 300lb-ft

 

[blacksport]

g-wrench with 40k on it......leave it alone....

 

[skylark]

Honestly, I'd recommend buying a known running vortec 350, swap a cam and go from there. I'd find a buyer for the 305 while it is in your truck and swap on a weekend.

The 305 isn't a decent performance engine and it will leave you disappointed. The 305 vortec heads aren't much better than your tbi heads. I believe that the cam that you're looking at is a flat tappet which means that ideally you're going to run oil with zinc in it. The vortec 350 has a roller cam. Realistically in most cases by the time you buy the heads and do the labor to install them, you'd be money ahead to swap.

 

[slowburb]

^ He's right. Even a low to mid mile JY 350 would be more ideal than cracking open the 305.

 

[884x4310ci]

Any heads are better then the swirl port heads.
So vortec heads. A matching intake will make a big difference.
But don't expect a rocket.

 

[Wade]

Honestly, I'd recommend buying a known running vortec 350, swap a cam and go from there. I'd find a buyer for the 305 while it is in your truck and swap on a weekend.

The 305 isn't a decent performance engine and it will leave you disappointed. The 305 vortec heads aren't much better than your tbi heads. I believe that the cam that you're looking at is a flat tappet which means that ideally you're going to run oil with zinc in it. The vortec 350 has a roller cam. Realistically in most cases by the time you buy the heads and do the labor to install them, you'd be money ahead to swap.

^ He's right. Even a low to mid mile JY 350 would be more ideal than cracking open the 305.

I should have mentioned, it is an 89 Firebird, only relevant because it has a 300lb-ft rated T5 that I don't want to blow up. So any engine I toss in should stay under that rating. Again, super mild, just looking to bump it up a little bit, but I'm new to this and looking for guidance

Here is where I need some experience;
Correct me if I'm wrong, the Vortec 350 makes like 255hp, 330tq. I suppose I could drop a junkyard vortec long block into the car, but I would need to de-tune it a little bit it in order to keep my T5

A second option is heads, mild cam, and intake on my current 305. I hadn't considered the zinc oil, so could I use a stock cam/lifters out of a vortec truck motor with that combination?

A third is a 350 Tbi long block, what about that? I could get my hands on one a little cheaper, and 180hp/300tq is probably safe with the T5.

 

[884x4310ci]

If your not looking to make too much power. Keep the block you already have. If it's in that shape.
Get a cheap summit brand cam.
How much can you get the heads for ?
If you get vortec heads you need a vortec style intake.
And th I style vortec intakes are expensive. You will be better off getting a 4bbl vortec style intake and get a th I addaptor.

 

[884x4310ci]

https://www.summitracing.com/int/parts/sum-1102/overview/make/chevrolet

https://www.summitracing.com/int/parts/pfs-52007/overview/make/chevrolet
https://www.summitracing.com/int/parts/trd-2211

 

[Wade]

If your not looking to make too much power. Keep the block you already have. If it's in that shape.
Get a cheap summit brand cam.
How much can you get the heads for ?
If you get vortec heads you need a vortec style intake.
And th I style vortec intakes are expensive. You will be better off getting a 4bbl vortec style intake and get a th I addaptor.

I can get the heads for $140
I plan to get a carb intake for vortec bolt pattern if I go any route involving vortec heads. I'll probably swap to carb, so tbi mounting and egr aren't necessary.

 

[98 Nitro]

I would go with a 305 vortecs, they flow better than any other 305 head and then a mild cam maybe the smallest Lunati Voodoo cam or....look for a good running 305 vortec engine out of a truck they usually sell for cheap. 285 tq Lbs and 230 hp much better than tbi305.