1978IROC

Hello, new here, old project car has sat, life in the way.


In 1989, I had an '85 IROC and really like the system, and I had a nice '78 Camaro with a 305 2bbl that I knew I didn't want to keep. I happened upon an '87 305TPI/700R4 with 5K miles for $1000, thinking I'd swap in a Z28 posi rear and this TPI/700R4 set up with a Bill Howell Harness. Then I found a WS6 rear end and completely rebuilt it with 3:90 gears, all new, axle to axle. Car is completed, and then it has sat, getting ran only very rarely. A lot of time has gone by. I reassessing what I have, and since it's all there, nearly new, although a 305, I don't think I'm going to build more cubes. I've considered very minor changes to enhance what there is already there, without going down the rabbit hole again. I'm not looking for much gains, but think there is some easy power to gain. Airfoil, gasket matching runners, plenum, base, aftermarket chip-all the easy basic stuff has been done. Custom K&N filer tapered cylinder laying on wheelhouse liner. Motor is 'SDD', 1987 Firebird, car and powertrain look mint. Running MAF/O2 in old long tube hooker headers, 2 1/2" exhaust. It looks like GM put it in there, aside from the K&N. It's stock and done at 5K, the bore size and heads limit any big gains, and to be honest, it's sorta quick now and I've nothing to prove to anyone anymore. But:


1) Can I stuff 1.6 ratio roller rockers under the stock center bolt valve covers with enough clearance, rather than recam it?


2) I figure since it's all pretty fresh I should just stick with what I've got, but what will I gain with Extrude Hone?

Street Lethal

iTrader: (16)

It's not the bore size that is the issue, it's the quench, stroke and compression, this is what makes most cringe when using a 305 for a street application. Racesaver 305's make great power, but they wring those engines out to make that power, would be a dog on the street. Best option for 305 diehards would be to stroke it, but after all that money spent you could have gone 383 for less. If you're happy with the power you already have, as you stated, then I'd say forget the 1.6 roller rocker concept and get an EBL Flash so you can dial in what you already have. If the engine is stock with only that many miles, then leave it as is. Just enjoy it for what it is. That's my two cents...

- Rob

Aaron R.

This needs to be stated every day. Maybe a stickie that says just that and nothing else.

Andreas_91GTA

Yes, narrow body self aligning rockers will fit. However, I and several others found out that the rocker can press on the valve spring keeper instead of the valve itself. That can end up in a nightmare. I ran this way for 100's of miles until I changed heads and actually saw what had been going on (scratch marks on the rockers)
Dont know if stamped steel roller tip rockers suffer from the same problem.

1978IROC

I get that the 305 is not the best way to make power.

My initial plan was to just swap in a Camaro Late Gen 2 Z28 motor and Z 3:73 posi rear end in, but I found a deal on the LB9TPI/700R4, practically new for $1000. It had a 2.41 non posi, the wife bought it new in '78. I had intended to just use the LB9 to get the car running, stand alone harness, relays and computer functional, and learn more about the TPI system, then go for a longblock 350. I had bought and still owned an '85 IROC TPI, but right after '85, TPI computers had changed, roller cams had just come in, and remember, back when I started in about summer of '88, there was no internet, and Bill Howell, ex-GM engineer for TPI, was the only source for a harness and how to. There was hardly any aftermarket stuff for TPI. I knew TPI did not rev over 5K, and that over 3:90 wasn't advisable but wanted a really street-able zippy cruise car, so opted for the 3:90 just to get up into the power band quick, since it was just going to be a cruising car, get out of the throttle and throw it into 4th. I built a 3 core brass radiator, leaned it back like the IROC and put the dual fans on it. I put Herb Adams sway bars front and rear, 1.38" and 1.25 in poly bushings, the front has top and bottom Heim connections. I used an aluminum driveshaft, and built the WS6 Gen 2 Trans Am rear. At the same time, I had a young son and bought a big block 22' boat, which stole all my summer weekends.. The car languished, basically done, but not totally sorted, while I swapped the 454 motor in the boat for the 502. The boat got a 578hp/573tq 502 and the car continued to languish.

Then the wife went bat **** crazy, my job went out of business and I wound up divorced, but kept the Camaro and the boat. More life **** got in the way.

At this point, I'm not going to build a bigger motor to put under the TPI, don't want to pour a lot of money into a 305, don't want to go hi flow aftermarket TPI parts, just looking to put simple and cheap improvements into what is there. If I wanted a really fast car, I'd have used a carb on a 383.

I've got 35 years into this, the Camaro is still real clean, low miles, and the TPI looks fantastic with hood open. I realize almost no one is going to get this situation. Again, I built this long before the internet.

dmccain

iTrader: (2)

Get some DYNO DON headers and y pipe. 3in exhaust all the way out. 2200 stall and a gear such as 3.42 or 3.73s. Shift kit in the 700r...It will feel much better.

SbFormula

the famous "I just want a bit more power".. out of a 190HP '80s engine

OK, let's get it to 210, 215 or maybe 230... WOO HOO

erik69&85

iTrader: (1)

I run stamped steel 1.6 roller rockers on my 92 305... It adds a nice initial kick of the line... Not much at the top end .. they fit fine... I used the summit racing ones... Not too pricey... I thought it was worth it... It made a nice driving difference...

But someone also feels different... I stand by my car and that it was a nice upgrade...

Running a stock cam.... Factory.

1978IROC

Thanks for the reply. My 1985 IROC had the good cam, and I was wondering if I could just crutch the LB9 cam and stay with stock valve covers, but I did the math and 1.6's only gets me half way back to 215hp cam, so I'm gonna leave the rockers be.