syoung_2000

iTrader: (3)

Hey everyone!

I'm relatively new to the site but have spent a ton of time reading threads. I didn't wanna get burnt by the "Use the search box!" response so after some research here it goes....

I recently purchased a 1991 305tpi automatic with 102,000 and a solid body for a heck of a deal. The transmission was toast and engine was leaking oil in a few spots. A good transmission rebuild was quoted at $1200.

So...I purchased a WC T5 from a '92 at a great price. Engine and tranny are now removed. I'm working with the engine I have.

I got the Magnaflow cat-back 16829. I want to add the Hooker 2055, 3" cat, and drop in K&N filter. Of course I'll be replacing all gaskets, tune up items, etc...

I just want it to sound awesome and add a little pep to it. While researching, it appears the next thing to do would be have the heads ported.

I called a local place that does this kind of thing and they said they would port heads for $400 and grind valves for $170. They didn't think it would be cost effective for me to have the 305 polished too since I'm not trying to squeeze every ounce of horsepower out of it. In other words, bang for buck.


Does porting w/o polishing sound like good advise?
Would you do the valve grind?
And finally...Does this all sound like a well balanced, performance upgrade combo?

I don't have a really high budget for this build. Just moderate stuff. No race tracks or whatever.

If there's anything you'd add or take away from this, let me know.

Thanks for all your help and advice!

-Shawn

305sbc

iTrader: (3)

In the 305 heads, the stock valve size and design is the major restriction to air flow.
There is information in some links in my signature for budget upgrades to the 305 heads.

The only porting you need with the valve upgrade is to open the bowl/seat area to about 90% of the new valve diameter, and blend into the floor of the port. Your cylinder head guy will understand what this means.

Your heads (with 100,000+ miles) will already need the guides refreshed anyway. There are bronze guide liners that will resize your guides (after reaming) to 8mm. (see info at links below) The larger size LS1 style valves have 8mm stems, as opposed to the 11/32" stems you have now.

I would go ahead and have the guide tops/bosses machined down to 0.500" O.D. and for more valve lift clearance (for future cam upgrades). I would also have the studs pulled and machiningg done for screw-in studs and guideplates. The pushrod slots in the heads will then need to be opened up.

You will need to use different (non-self-aligning) rocker arms after the conversion.

The power gain with this upgrade should be between 30 and 40 horsepower, assuming you keep your stock camshaft in place. The great part about the gain from the head upgrade is that it gains power across the board, - every RPM instead of shifting your torque peak higher in the RPM range. You will not lose fuel mileage or drivability. You will not upset your computer's ability to function correctly (assuming no other changes).

For some added performance to compliment this valve upgrade, you can have the combustion chambers deshrouded a bit (should be done during porting), and add higher ratio rocker arms.

VincentZ28

iTrader: (2)

Don't get the Hooker headers. They are not that great for future up grades. Get Dyno Don headers. They are 1 3/4 tubes with a ball-n-socket collector( no gasket needed). They are the best on the market. Also they will work with all straight an angle plug heads without burning the plug wires. Dont waste your money on any other headers. I wouldn't put too much money in the heads because you will in the near future you will want to upgrade to a 350cu. Pull out the air filter and cut completely the bottom of the filter box. That's all you need to do.

spurgeon76

http://www.ws6transam.org/ported.html

Check out this link, and see what a member did with his 305 heads and the results.

VincentZ28

iTrader: (2)

I have seen a stock 89 305 5 speed IROC with just a full exhaust system go 13.8@101 at Pomona with 3.45 stock gears.

BuzzLOL

.. If paying that much to mod heads, would consider some new aluminum heads... or rebuilt 'Vette -113 aluminum heads which have same size 58cc chambers as 305 heads, but bigger valves and ports, lower weight...

VincentZ28

iTrader: (2)

Save your money for a crate 350 $1700 for a short block(L31 Vortec).

BuzzLOL

.. Can get a fresh 350" shortblock for $850 here, or they'll build a whole engine to your spec.s at the lowest price around with like USA-made Edelbrock E-Street ($909/pair) or Profiler ($950/pair) aluminum heads:

http://www.wholesale-engines.com

ninetyone

iTrader: (2)

Was your car a TBI car before? I noticed you have 2.73 gears.

305sbc

iTrader: (3)

A 305 TPI with stock cam, 5-speed, and 2.73 gears should get very good fuel mileage.

VincentZ28

iTrader: (2)

Was I was talking about is a GM short block with warranty. It could be less than that. But I think he get the point. Go 350!

syoung_2000

iTrader: (3)

It's actually 305tpi from the factory, 700r4 and 2.73 drums. Kinda boring in my opinion.
Bought it Sept. 2011 (a week before shoulder surgery) with oil leaks and a burnt out transmission.

I only got to drive it the day I bought it and the car limped home on a trashed tranny and was parked :-( That's when I took the picture that's under my screen name.


Hope to have it back together by late spring this year. My goals this year are the 5 speed conversion, 3.42 disc rear (if I can find it), and seal up/tune up the motor. Already have Magnaflow cat-back. Just looking for headers.

Perhaps after this years money splurge, next year will bring on the 350, but getting my first American muscle car on the road before summer is the biggest goal for now. Hello T-Tops!!!

I'm 30 years old, so I'm past due for the V8 car! I've been dreaming of GT body 5.0's since I was 15 (please don't kick me out!), but this car fell on my lap for cheap and I'm really excited about it! I've actually been converted! With any luck I'll be leaving a few 'stangs in the dust.


You all are insanely knowledgeable! My heads been hurting since I joined the site, from reading these threads!

Thanks for all the help.

-Shawn