I know about the search features and have used them but there is so much info I get lost. my problem is this. what do I do to fix my car? 1986 z28 iroc z 305 tpi 116,000 miles. its smoking on startup (blue), and on wide open throttle 4500 to 5000 rpm (blue) , the valve train is noisy on acceleration under a load. 5w 30 oil is used. I have $2000 dollars to fix this engine or remove and replace it with a 350. I am looking at 300hp for a goal. I would really like to retain the tpi to remain decent with fuel economy and somewhat original to the car.

any advice is greatly appreciated.
thanks Ryan

 

GM Performance Parts 350ci / 290hp Engine

+

gasket kit

=

$2k





then sell you old parts that are still good, gives you $$$$$ back i your wallet

or sell your old stuff first, and get the

# GM Performance Parts 350ci ''350 H.O.'' Engine330 hp

 

Retaining the TPI is the biggest bottleneck (and expense) to getting to 300 HP, if comparing the 245 some L98's are rated at. But, it can be done.

The HO crate would be pretty expensive, because you need a $400+ base to be able to hook the TPI to Vortec heads. Then you'll suffer the "TPI" factor, and be below 300 HP again. In order to get back to the 330 the HO puts out with a carb, Scoogin Dickey had to upgrade the cam & heads, and then overshot a little and got 357 HP (remember, those crate HP ratings are flywheel gross, not the flywheel net you'll see for new car ratings). The total cost of that package is well over $4000.

If you're willing to do a little work, you can get and rebuild a 350 shortblock for less than a grand, take your 305 heads and have 1.94" intake valves (and perhaps 1.60" exhaust valve), do some basic do-it-yourself porting, then with a nice cam and headers, you'll get your 300HP within your budget.

 

I am going for this setup:

24 lbs injectors acc150824
chip jet chip jet18614
350ci 290hp/325 tourqe nal12499529
headman headers hed68470
y-pipe hed17470
flexplate sumg100sfi

all through summit racing

any suggestions i will greatly appreciate...Ryan

anything i have forgot ????

 

That's over $2000 and under 300 HP.

Is that a problem?

 

Will that Goodwrench 350 that is 290hp accept the stock TPI system?

 

over $2000 is not a major problem. It does not seem like much can be had for less. I was niave to the costs. I figure thats a good place to start engine wise? summit racing tech support stated that the hp rating would hold true even with the tpi. I know that it has been stated here that the tpi will not reach this power stock. where is the bottleneck in the tpi? cant some of the parts be upgraded? to flow better to reach 290-300hp. I am looking for a street car to drive 5 days a week in the summer not a race car. possibe or not 290hp with the setup I stated above I am changing the injectors and will get a chip.

 

The '85-'86 TPI is a direct bolt-on. '87-up TPI will have different angle center two intake mount bolts on each side.

 

For just the engine, yes. For the project, it's a little low. For 300HP, it's only the beginning.

The bottlenecks in the TPI are the runners (diameter & length), and plenum & base ports. For this HP level, shorter aftermarket runners and some basic porting will help a lot. The "tuned" part of TPI is really the problem, as it is "tuned" for the lower RPMs for the SOTP feeling of power (and to some extent, fuel economy). Since these crate engines are rated gross flywheel horsepower with carb, good intake, headers, no air cleaner or accessories, you're always going to lose some just by putting it in the car. Although I haven't seen a lot of actual TPI dyno tests, the results have consistently been lower than the same or similar engine with a carb.

The TPI forum is the place to go to understand what helps that system.