Okay, I went out to the drags for the first time in my Trans Am. I have recently rebuilt my 305 TPI and put a mild cam in (Comp Cam 12-208-2 to be exact). It is bored .60 over with hyperutectic pistons, but other than that it is completely stock. Here is my best run: 60'- 2.470
1/4- 16.804
MPH- 81.30

I know that nobody can just tell me exactly why my times are so bad just from what I've said so far, but I was looking for some insight as to what to check over and maybe mod. Also I did notice that when I got into 3rd and 4th it would sort of bog down and lose it's pep. That's how I lost a few races. Any suggestions would be highly appreciated. Thanks.

 

Well, start with the little stuff 1st. Wires, plugs, air filter, fuel filter, converter, timing, etc.

 

you definitely need to work on your 60 foot times, what kinda tires and suspension are you running?

 

the 60 ft time doesnt mean anything when the car should be trapping at 96..and you wont gain 2 1/2 seconds by knocking 4 tenths off the short time

is your can an auto or 5 speed...if its a 5 speed what year is it..
if you have an auto car your tv cable may need to be adjusted

after youve done that, if its needed, check your ignition stuff

 

It's an '86 with an automatic 700R4 rebuilt. The suspension is bone stock and I'm running 235/60 15 radials, brand new. F-Crazy has a good point. I shouldn't be only hitting 81 at the most through the speed trap. TV cable? What is that? See, I know my 60' times aren't the best, but considering the condition of my exhaust I can see why. Along with the fact that my alternator fan has chewed a hole in the air intake box. I was keeping up with some decent cars until about the 1/8th mile when they would just blow right by me. Let me know what you mean by TV cable, thanks.

 

Why did you rebuild the 305 instead of putting a 350 in, I'm just wondering? I see TPI 350 blocks quite often in the trader here in Indy going for around $200. As for your car not running good, after you check the basics, like seeing if you have a couple of roasted plug wires or not which is common for a car running like a dog, i'd recommend doing a leakdown test. Do this after you check the basics first. This can be time consuming, you need to check your whole ignition system, all your ecm sensors, you fuel system, and of course you need to know your compression. After you check all this stuff out and your car still is a dog, Do a leakdown test to check out the rings. I'd bet your problem is rather simple though. Good luck finding your modification gremlin(s).

 

You've definitely got a big problem. My car is an almost completely stock 2.8 and my 60' time was 2.61. Have you checked your timing, spark plug gapping, fuel filter, air filter, and so on? Good luck on finding your problem(s).

 

Alright, today I got into the engine pulled all the plugs and wires. Here's what I've found: All plugs have that nice light tan color on the tips except one. One of them found in the #3 cylinder has a good amount of black grease on it. Also one of the wires going to the #8 cylinder was getting burnt by the manifold. So I'm going to throw some new plugs and wires on and take it back to the shop who rebuilt my engine and say WTF? If I'm right, does the deposit of black oily grease on the plug mean that either I have a bad piston ring or bad valve seals? Well that's what I've found so far. Thanks for all the input so far!

 

Okay, took her down to the shop today and here's the diagnosis they have prescribed: It was a carbon build up on the plug so they told me to put some fuel injector cleaner in it and drive it on the highway for like 200 miles or something. Personally, I'm not driving it in it's condition further than I can afford to tow. So I'm thinking it has to be a fuel problem. I don't know a whole lot about fuel injection much less the TPI setup. Any suggestions for what I should check?

 

If it's a rebuilt rescently motor, couple things I know of could have happened.

The rings on that cylinder didn't seat right.....

That cylinder got junk on the plug from the get go before the rings seated, and fouled just that plug....

Your tuneup is bad...

CHECK EVERYTHING. Timing too!

 

Thanks for the suggestion. I ran a compression test the other day and I got good readings, about 140-150 psi on each cylinder. I checked the plug again a week after I put new ones in and sure enough there was more oil building up on the #3 plug. So what I'm guessing is the valve seal is the culprit. Timing is at 6 degrees advanced which is what it calls for. I have noticed that the idle is up and down between 6 and 8K. I think it's a vacuum leak somewhere. It is also leaking oil so I'm taking it back to the shop next week and have them give it a good look down of everything.

 

Bad valve seals shouldn't foul the plugs because once the engine fires, oil doesn't get down there really.

 

Yes it does, and yes they will.

 

here are the specs for my cam: Lift- .442/.465, Duration @.050- 211/221, Separation- 110.0. Do you think this is too much of a cam for the stock 305 heads to handle? Could this be part of my problem?

 

wow that cam is wayyyyyyyyyy to big for a 305! that things big!

 

Really? I had no say in what cam went into it, because I had no knowledge of really what to look for. I just told the shop that I wanted a pretty good power boost when I had it rebuilt. So this could be a real problem for me, huh? The motor is not even 6 months old and so far I am completely dissatisfied with it. What kind of cam specs do you think would be a good for my application?

 

Wow, those are good times for a 305 TPI, what kind of setup are you running, SLP Iroc-Z? Those are the times that I want to be running. Also, what kind of cam did you put in?

 

the 13.9 was witht he stock cam i now have a stock grind LT1 cam, got 3mph from that, car really woke up from that swap.

check out my cardomain it has all the details.

here