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geezer#99 · 09-27-2021, 04:21 PM

My buddy built a towing rig for his 5th wheel holiday trailer.
71 gmc with L88 spec 427. 12.5 to 1 compression. ZL1 cam. Idled rough at 1100 rpm. Hooked to a turbo 400 and 4.56 gear. Pulled at 65mph at 3200 rpm all day. Surprised a lot of people when he’d pull out and pass.
Rpm won’t hurt your motor.
I’ve run lots of big blocks from 396’s to LS6’s. They all liked 3000 rpm or more.

Looking at that chart, torque peak at 3000 is right where you want to run.

09-27-2021, 04:21 PM	#14
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: 1970 L47 400 BB Torque and HP chart My buddy built a towing rig for his 5th wheel holiday trailer. 71 gmc with L88 spec 427. 12.5 to 1 compression. ZL1 cam. Idled rough at 1100 rpm. Hooked to a turbo 400 and 4.56 gear. Pulled at 65mph at 3200 rpm all day. Surprised a lot of people when he’d pull out and pass. Rpm won’t hurt your motor. I’ve run lots of big blocks from 396’s to LS6’s. They all liked 3000 rpm or more. Looking at that chart, torque peak at 3000 is right where you want to run.