I read a "Best first mod?" question and instead of answering there i thought id stick this out in the open for all to see. Change your timing chain and gears. All the TBI engines (trucks and cars) have 4 degrees of retard on the cam put there buy the timing gears. This was done so these engines could pass emissions. Do your homework on whether or not you have a roller cam and if you do, buy a timing set for a tpi and if not get a timing set for an old small block. If you ask for a timing set for your tbi motor youll end up with the 4 degrees of retard again. Getting your cam "straight up" can make a difference.

 

Very smart. Thanks for the info.

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, Jon (91 RS too many mods to list), getting new engine in summer

 

What sorta documentation do you have to back up that TBI had a different timing chain set than TPI?

 

Would the down side to that be higher emmisions??? I can't do that then, but if it will still pass, how much of a gain will you get out of the tpi gears and chain? I was going to change these soon anyway. Would somebody please list all of the positive and negative affects this would have? Thanks.

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1989 Firebird Formula L03
Stock except for K&N, Flowmasters, Centerforce Clutch, MSD 8.5, and Accel Cap and Rotor. Much more to come.

 

Ive never heard of or seen them as being different. Thats why I'd like to see some sort of proof, because I would really hate to see someone tear out a timing chain thinking its different if its not.
All the aftermarket chains are the same, TBI or TPI. Thats why I'd like to see something that says from the factory they are different.

It wont keep your car from passing emissions. Too small of a change.

 

Where is the proof?

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, Jon (91 RS too many mods to list), getting new engine in summer

 

Call your local parts store and have them look up the timing sets for both engines. they will be different.

 

An aftermarket set like an edelbrock shouldnt be retarded though..

 

And because the part number is different (you say) the timing is 4 degrees retarded?

Actually I went ahead and looked it up for myself, both in the aftermarket (Cloyes, Sealed Power) and at the dealer, and the part numbers arent different.

Whoever told you they arent the same was mistaken.

 

That was a trick used by F*** a few years ago, doubt if they still do it anymore.

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Chronologically challenged. But still kicking!
92 CAMARO RS
305 TBI 5/spd (now TPI)

'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+

 

Sorry guys. Looks like I was wrong. I checked into it again and it seems the timing sets are the same. I could swear i saw differently before though. So disregard that first post. But the timing is still retarted. ive degreed the cam on a couple of these and they have been 4 degrees back. so just check it if youve got one apart

 

I don't know about the timing set retartding the timing or not but I do know that I used a flat tappet hyd. cam in my engine for the rebuild. My roller rockers were thrashed and i didnt want to shell out the money for the new ones so, I told the motor supplier to leave the cam out of my short block then I went and had the cam ground to Crane's specs for $40.00. I slid the cam in and ran it straight up with the cheap timming set with the motor and it pulled like a 350. I also advanced my timming from 0 deg to 9 deg a few weeks later which made another hugs difference.

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1988 Camaro
305 bored .030 over
Stock TBI
Aluminum radiator
No smog pump
cam ground to crane specs
no thermostat
other than that its bone stock and ran a 16.4 with earth shattering wheel hop and a 2.88 60 ft time. (this was with the rebuild and cam only)

 

LOL.......forgot the main reason for my post. I also wanted to mention that I passed my emissions test with all my mods except for the smog removal........that was done recently since I have no emissinos tests anymore.

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1988 Camaro
305 bored .030 over
Stock TBI
Aluminum radiator
No smog pump
gutted factor cleaner
cam ground to crane specs
timing advanced 9 degrees
no thermostat
other than that its bone stock and ran a 16.4 @ 82 mph with earth shattering wheel hop and a 2.88 60 ft time. (this was with the rebuild and cam only)

 

I degreed my compucam on my 1992 RS.
The timing set was a Cloyes true roller that was very expensive for a roller car motor.My thought was this,Cloyes use to make timing sets for GM and yes they have been known to be retarded(by as much as two degrees).
Sure enough mine was back 1 degree.I cured it with a offset bushing.
The car starts perfect and runs like a raped ape.
Timing is everything on a TBI anyway because the injectors fire off the Hall effect pickup in the DISTRIBUTOR.