Hey guys here's the story...

I bought my car from this guy who does NOT remember the build specs of the engine, which was a 305 tpi. He said that it was completely done over... (Forged everything... bored over 0.030, pistins, rings, crank, bigger GM cam, ported and polished heads, everything new and done over...)

It is still a TPI but I upgraded the intake system with AS&M runners, ported plenum, accel lingenfelter manifold. So the engine right now is running good because i got a stock-type chip from TPI PARTS.net with the correct settings (EGR delete, smog delete, etc.) The only thing is that I do beleive my engine should make alot more power that it is... On the dyno it currently makes power up to 4800 rpms and then coasts until maybe 5000-5100 rpms then starts dropping... 5200 is where it shifts..

My question is this: With a proper tune, I know for a fact that I will gain many ponies, also I think the pistons are lower compression pistons so i think maybe i could raise timing too? I'm not sure... But how can I find out what Pistons I have, what cam I have, and what compression I have??? It has been driving me nuts I want the car to be at its peak performance... I will be racing it in the spring against a 2005 BMW M3... They do 13.6 - 13.8 on the quarter mile. I'm sure I can do this with proper tuning and a couple other mods...

Do i have to remove the engine just to know my cam specs? How can I do this??

Thanks!
-Marc

 

So this guy didn't have any documents to provide? The only way to know for sure is a tear down. People are so dishonest now a days you might have a stocker rebuild. Can you hear the cam at all? What kind of power did it make on the dyno?

 

He said he lost the documents... I dyno'd it after i put all the ported stuff on it... It sounds like it has a bigger cam but not that big... But it does make quite the powerful sound... Like vibrates the windows in the back of my house when it's idling in my driveway in front... I could take a vid in 2 months when i take it out... It looks rebuilt.. Engine looks newly painted and valve covers are new.. so it looked beleivable.. When I called him a year after the sale and told him i wanted to get new heads so I asked him what the cam was he said don't bother touching the engine everything was ported and polished & done over etc... So I don't 'think' he would lie about it a year later.. I don't think he would have anything to gain out of it??

It made 271HP - 354TQ @ the crank... Wheels was like 215 hp and almost 300tq... I know that's high for a 305 but I dyno'd it after I re-did the intake and exhaust and all that stuff.

Also... What is a tear down? It sounds frightening... And lots of work!

Thanks!
-marc

 

I made 216 at the wheels as well. I have LT4 cam (so ive been told), edlbrock headers, AS+M runners, Edelbrock lower intake, ported plenum, 3 inch flowmaster exhaust. Those are the big things done to the engine. There are some smaller things too like an adjustable fuel regulator and such. Yes sounds like you have a healthy 305 there. Mine surprises a lot of people when they think its a 350 and i smile and tell them its "just" a 305.

Also if your making that power there is no way its a stock cam. 86 got the peanut cam and that would hold your motor back big time.

 

Tear down = Pulling the engine and disassemble. Hmmmm, well you definietly have more than stock. And the numbers don't sound to far off from what most warmed over 305/auto's do. Is the TPI still completely stock? If so you got some porting ahead of you.

 

That's welcoming news! Good to hear i wasn't screwed over all this time... Man .... The tear down is a bit much... Isn't there a way to know the cam another way? I heard something about maybe pulling it out by the front and checking the model number ?

Yeah my TPI intake is all ported... Plenum is stock, but ported... Runners are used from AS&M (which are stil long tube but tubes are larger), and manifold is a accel lingenfelter... I also have edelbrock headers and gutted cat with 3 inch flowmaster.. Billet AFPR at 42psi (kinda low, but the dyno guy turned it down and said it gave the most power), K&N filters, I'm not sure about the timing....

Anyways, I really would like to tune this thing cuz I did a run at the track on a cool day and i only did a 14.6... My reacton time was bad at 0.9 seconds and my back tires aren't the greatest... Maybe that could help... I am aiming for high 13's i think that's possible.. Once I do that I will be happy.

Thanks guys!
-Marc

 

Your parts list is almost identical to mine and your making almost the same horses. I would guess that your cam is around the same as mine (LT4). Might not be the exact same but that gets you in the ballpark.

 

The guy said it was a GM cam but he can't remember which one... If that is the case, would I be able to get a custom tuned PROM burnt for it? What if it was not the LT4 cam but close to it, would it blow up the engine if I tried to run a chip burnt for that cam, but I had something different?

Thanks!
-Marc

 

No you wouldnt but if its not the cam then you will not be running as efficiently as you can. Come to think of it you said it didnt run perfect and it still made that power? Chances are its not the LT4 but something close. Without knowing what cam it is i would think your best bet is to start reading up on how to burn chips yourself. I know nothing of this since my car has a chip burned by TPIS. It was done before i got it. Im sure there is more power to be had in my combo if i learn how to burn chips but thats an art and when u dont understand computers too well like me...no good.

 

I checked on Scoggin Dickey's website.. They sell two different LT4 cams.. As per the site:

One is a GM factory replacement cam with 203/210 Duration @ 0.050 Hyd. Roller Cam. Apparently this one was used in 96 LT vettes and with 1.6 Rockers. Mild camshaft with smooth idle can be used in all 1986-99 305-350 engines originally equipped with a hydraulic roller camshaft. It can also easily be used in non-roller 1986-99 305-350 enignes when used with lifter kit 12371042. Works with stock computer on most computer controlled engines. This is an excellent power adder for 1987-95 TBI pick-ups and TBI/TPI cars. Can also be used in non-computer controlled engines.

The other is a GM HOT LT4 Cam with 218/228 Duration @ 0.050. LT4 Hot Cam can be used in any late model (1986 and newer) Small Block Chevrolet block for a significant horsepower gain at a reasonable price. This camshaft offer a slightly rough idle in most applications. Computer modifications are usually required, can be used in non computer controlled engines. Note : The LT4 camshaft P/N 24502586 was designed to be used in a number of different engines. Therefore, the following change may need to be made to allow for correct assembly of the engine: For LT1 and L98 engines 1995 and before, the dowel pin in the end of the camshaft must be pushed in so extension from end of cam is .30 +/- .01" , the same as the production part. For 1996 LT1 and LT4 engines, the dowel pin is in the correct position, extending .620" from end of camshaft. This camshaft has a fuel pump lobe

Must be one of these cams then? From what I'm reading, it sounds like the first one, NOT the HOT cam. My dad even said it sounds like a mild cam. THe idle is fine now that everything is working properly... That must be why the stock chip still works good maybe? What are your thoughts on this...

Thanks guys I appreciate the response! I'm at work right now but I'm refreshing this page often to check for any responses lol.. thanks
-Marc

 

Replying to Subroc,

The car runs decent but it should put down better numbers for everything it has... The PROM burning thing does not scare me I am good with computers (I am 22 years old and that is my field.. computers!) .. The only thing that scared me about it is that if I mess with spark tables and timing and fuel and all that... What if I make an adjustment wrongly and then blow a piston?? I know the basics about engines but knowing fuel and timing is over my head, atleast for now I don't have the resources to learn that... But I have laptop and I don't hav any problems buying the software to get it done. By not knowing anything about timing/fuel/spark, would I be playing with fire?? Just don't wanna buy all that for nothing.

Thanks!
-Marc

 

I would spend a good amount of time on the prom burning board and see what your feelings are on the subject after that. Its a science in itself. I have the LT4 cam not the hot cam. If you have a fairly mild idle and it runs decent with a stock chip then i would say u have the normal LT4 cam or something with similar specs. Mine will run on the stock chip but not as well as with the custom burned one.

 

Hey thanks for the reply again..

The car runs decent enough although it was surging at times, but now it seemed to have settled with a prom with EGR delete, smog delete, etc. it idles around 6-700 seems to be running stable... Took a lot of time and work though. The hypertech chip made it run like crap although it felt alot quicker with that chip in there, even with it's minimal adjustments. For sure I beleive that the custom chip will make the car run more efficiently. I'll get reading on the PROM board and see what they say... I've read so much on there though... But everybody on there seems to know their cams and I feel like I'm the only one with this silly issue of not knowing his own cam. So basically I have to keep burning chips and upgrading timing and spark bit by bit and see what happens everytime? I guess it's best to read the boards..

Thanks alot atleast I know, somewhat, what kinda cam I have...
later,
-Marc

 

If your idle is surging, you might want to rule out other problems with sensors and such. Maybe type in idle surge in the search function and find out what could cause it ( i dont know off the top of my head). If i were in your shoes i would do everything possible other than trying to tune the computer just to eliminate other possible problems and save yourself the headache of tuning a engine when you dont know exactly what cam it has.

 

My reply earlier to the tear down was to figure out what internals you had. To figure out specifics on the cam, you would most likely have to pull it to get the info off the backend. As for the computer tuning, read, read, and read. And yes, if your not sure what your doing, you could pop the motor. Even if your good with computers, the program is just a bunch of tables with numbers. It took me a couple months of tinkering with TunerCat and reading before I got comfortable. You will need a good scanner too as you will need to know how your changes are taking effect. Don't worry if you never find out about the specs on the cam. You really don't need that info if you will be doing this yourself. Go to Moates.net for everything you need to get started. Good luck!

 

I guess I will do it the hard way and do some great trial and errors! Thanks I will get some moates stuff to get started.. Hopefully the PROM gurus will still be there when I need a helping hand...

Also, I replaced most sensors but I have new TPS, IAC, O2 sensors I just have to install them, and ofcourse calibrate them properly. That would mean every sensor on this car has been changed, so there can't be anything wrong with it. Although the surging stopped when I put the TPIPARTS.NET chip in so it must have been the new parameters on there that fixed it (disabling egr and smog in the chip)

Anyways... Thank you all for the very helpful info! I hope to be able to improve my car's performance this summer when I take it out!!! Have a good one,

-Marc