Motor box after rebuild

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   I experienced this when I installed some aftermarket manifolds on some Edelbrock heads. Not sure which was the culprit, but the motor box wouldn't 'settle' on the floor. Out came my grinder. I 'shaved' a bit off each side of the motor box. Boom. Done. Much cheaper, and the motor box is quite 'thick' in that area. 

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MourningWood Members Profile Send Private Message Find Members Posts Add to Buddy List Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 917	Post Options Post Reply Quote MourningWood Report Post Thanks(0) Quote Reply Topic: Motor box after rebuild Posted: April-15-2022 at 9:58pm
	I experienced this when I installed some aftermarket manifolds on some Edelbrock heads. Not sure which was the culprit, but the motor box wouldn't 'settle' on the floor. Out came my grinder. I 'shaved' a bit off each side of the motor box. Boom. Done. Much cheaper, and the motor box is quite 'thick' in that area.
	1964 Dunphy X-55 "One 'N Dun" 'I measured twice, cut three times, and it's still too short!"

KENO Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11112	Post Options Post Reply Quote KENO Report Post Thanks(0) Quote Reply Posted: April-15-2022 at 7:27pm
	I measured across a pair of PCM manifolds on a 351w today and got closer to 28 inches than 27 1/2 like the manual says, just so you have an idea. It was about 27 7/8 I not sure I'd machine an angle into the mating face of the flanges because then the 8 bolts holding the manifold to the head won't sit flat on the backside of the flange and would kinda affect their holding power unless the backside of the flange got machined to the same angle and that isn't an easy area to reach

JoeinNY Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5698	Post Options Post Reply Quote JoeinNY Report Post Thanks(0) Quote Reply Posted: April-14-2022 at 1:41pm
	Edit - watched the video and the risers are not different- More information on the heads and other changes would be helpful, there are aftermarket designs with raised exhaust port locations for better exhaust flow. Agree that a good machine shop putting on an angle would be a solid option if they are stock valve covers you would likely have enough clearance to tilt in. I would put on of the old manifolds back on and confirm it also hits the box and maybe have it cut at an angle to test before adjusting the new ones
	1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" Holeshot Video

GottaSki Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3363	Post Options Post Reply Quote GottaSki Report Post Thanks(0) Quote Reply Posted: April-14-2022 at 12:44pm
	A machine shop could resurface the manifolds, and cant them inward 2 degrees or so, that would get you a half inch each
	"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole

beebe Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: May-15-2017 Location: Arkansas Status: Offline Points: 32	Post Options Post Reply Quote beebe Report Post Thanks(0) Quote Reply Posted: April-13-2022 at 1:39pm
	Nice resource. Thanks! It turns out my manifolds and risers are an inch further apart than they should be. But as far as I can tell the new manifolds are the same size and shape as the old ones. So I think it must be that the heads are a different size/shape. I guess I need to find an alternative aluminum trim for the bottom of the motor box that is slightly taller. Thanks!

KENO Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11112	Post Options Post Reply Quote KENO Report Post Thanks(0) Quote Reply Posted: April-13-2022 at 7:19am
	If you go to page 10 of the link below you'll find PCM's measurements of about everything you can think of on a 351w with the exhaust manifolds installed. For example 27.5 inches wide at the top of the manifolds outside edge to outside edge. Then if you have a different width, you can measure manifolds, risers to see if it's due to them or the aluminum heads. link

beebe Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: May-15-2017 Location: Arkansas Status: Offline Points: 32	Post Options Post Reply Quote beebe Report Post Thanks(0) Quote Reply Posted: April-12-2022 at 11:10pm
	My motor box won't fully close after having the engine rebuilt. Any ideas? Video explanation here: https://www.youtube.com/watch?v=Rz1AshaURnU

Motor box after rebuild

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