I just installed a 355 in my 88 Firebird. I started it up yesturday and had it running for about 2 minutes when the headers start to glow red hot on both sides. They actually burnt a plug wire completely off. Could the timing be that far off that it would cause it to do this or do I have other problems. I don't think the exhaust is clogged because it is fairly new. Any suggestions would be helpful.

 

Could be timing or too rich/lean. Please give COMPLETE specs on the rebuild why you had to rebuild.

 

Sounds like the timing is WAY off.

 

Somethings causing it to run very lean. A lean fuel mixture will cause the exhaust temperature to get very hot. At an idle, exhaust temperature should be around 600*. At WOT, about 1300*. It sounds like your idle temperatures are probably above 1500* if the pipes are glowing red.

Check timing
Check for any major vacuum leaks such as the port for the vacuum brakes
Check fuel mixture

Running lean can cause a lot of damage. Melted pistons, burnt plugs, burnt valves.

 

The motor is a 355 TPI motor with AFR heads and a comp roller cam. I don't understand how it could be running lean with feul injection. I think the the timing is way too retarded which is letting the mixture continue to ignite in the headers. Im going to play around with the timing tommorow when i get my transmission back. Thanks.

 

Has the car been tuned since you added the new heads and cam? The stock computer can only take so much variation from original specs before it freaks out. Check the timing for sure, but don't rule out a lack of fuel.

- Justin

 

No the car has not been tuned yet because i built the new motor then just switched out the stock 350 TPI motor with this one and haven't even had it on the road yet. I know tuning will help grealty for performance but will it still be drivable with the stock tune...I plan to get it dynoed tuned soon but will it be good until then.

 

Without a tune I would say it's quite possible that the engine is running lean. Check the timing, and then get it tuned. If you have an AFPR, crank up the fuel pressure a bit and see if that helps.

As a side note, if you are looking for driveability, don't count solely on a dyno tune. Make sure that your tuner also takes the car out on the street to see how it behaves under normal driving conditions.

- Justin

 

I had the same thing happen to my Superramed 383 when I put on a set of AFR 195's. First startup I noticed the headers glowing. I immediatley thought something was way off. I found I had a worn distributor gear and the timing was way off and the stock tune is not capable of supplying enough fuel for those heads. Like stated above check timing, get a chip done right away, we had to add all kinds of fuel!!