I have a TPI 305 in my car, it was a 305 TBI when it was in my old 88, it ran well, no strange sounds, good engine, but slow.

I pulled it, swapped it over to tuned port, put an LT1 cam in it, and originally had 19 lb injectors. I set the valves, then set the timing to 9*. car ran pretty quick, but whenever I got on it, there would be this rattling sound from the motor, I thought valves and readjusted, nothing, I thought maybe pre-ignition, but timing changes do not make any difference, nor does high octane fuel. it's definately not a rod knock, my knock sensor is not showing knock.when I lug the engine in 5th gear, the farther I push the gas the louder the rattle like sound gets. i put in 24# lt1 injectors, the noise is still there, unchanged, it has never gotten better, or worse, its only under load, i never hear it at idle. opinions?

 

Clutch throwout bearing? If you step on the clutch, does the noise go away? My LT1 has a pretty noisy throwout bearing that I have to get around to fixing sooner or later, and its really only audible at low rpm, but its definitely a rattle almost like spark knock.

 

definately not, before i swapped from auto to manual, it still made that noise

 

bump for peace of mind?

 

I had a similar problem in my 84 monte carlo it ended up being the flywheel and starter were jacked up I swapped em both out and sound went away

 

the car got a new flywheel and starter with the T5 swap. noise still prevelant