CLASS RACER FORUM - View Single Post - 335 HP 396 290 Head Casting Build & Dyno Test

HP HUNTER · 07-23-2024, 11:02 PM

Ok- so I finished the heads and started looking at the short block. The original plan was to run the reworked heads on the short block as delivered, but I wasn't happy with the short block and have started the rebuild on that. The dyno sheets I received with the engine showed a best of 441 HP I believe, I can post them if anyones interested, which sounds just right considering what the car ran. So what I found when the pan came off was stock GM rods with NHRA legal pistons with a standard ring pack, quite a bit of drag, the block was filled, .009 piston to wall clearance, a GM big truck pan with a crank scraper and a full length windage tray. Compression was way low considering what's allowed, probably 1/2 of a point, and then the offset head dowel pins and the butchered intake that goes along with that. On a good note the engine had an aluminum hub ATI balancer. So maybe we can get a nice performance gain, so I will go though the short block and get it together and run it on the dyno, then track test it in my F/SA Chevelle, and all by the time the air changes this fall.

07-23-2024, 11:02 PM	#34
HP HUNTER Senior Member Join Date: Feb 2012 Location: Colorado Springs Colorado/Thousand Oaks Ca Posts: 656 Likes: 82 Liked 372 Times in 129 Posts	Re: 335 HP 396 290 Head Casting Build & Dyno Test Ok- so I finished the heads and started looking at the short block. The original plan was to run the reworked heads on the short block as delivered, but I wasn't happy with the short block and have started the rebuild on that. The dyno sheets I received with the engine showed a best of 441 HP I believe, I can post them if anyones interested, which sounds just right considering what the car ran. So what I found when the pan came off was stock GM rods with NHRA legal pistons with a standard ring pack, quite a bit of drag, the block was filled, .009 piston to wall clearance, a GM big truck pan with a crank scraper and a full length windage tray. Compression was way low considering what's allowed, probably 1/2 of a point, and then the offset head dowel pins and the butchered intake that goes along with that. On a good note the engine had an aluminum hub ATI balancer. So maybe we can get a nice performance gain, so I will go though the short block and get it together and run it on the dyno, then track test it in my F/SA Chevelle, and all by the time the air changes this fall.