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jeff hedges

(10 posts)

12/20/2013 07:39AM

Main British Car:

Buick 300 / rover build
Posted by: Fozwanger
Date: July 27, 2019 08:43AM

Hi guys,

Itís probably been asked a million times before so please bear with me.
I have a 300 engine that Iím going to rob the crank and other bits and bobs from and I want to fit it into a late large journal cross bolted block.
Has anyone actually done this with first hand experience, will the crank fit without modification, Iím going to use chevy rods and I have a set of forged pistons,
Iíve read various conflicting articles so Iím looking for some first hand knowledge.
Also, has anyone successfully fitted a 340 crank into a large mains rover block (after reducing the crank mains) or is that just too much stroke for a rover block.

Any info greatly received

Jeff 👍🏼

Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Buick 300 / rover build
Posted by: BlownMGB-V8
Date: July 27, 2019 11:08AM

Jeff, the swing of the 340 crank is going to cause some trouble. The pan rails are narrower on the Rover than on the 300/340, you'd have to use a short rod and put the piston pin very close to the ring package and might have to use a small diameter pin but I *think* you can do it without having the pin bore intersect the oil ring land. Others have looked at it though and I believe the pan rails are going to be the real issue. That and the piston skirts. Then you'd have a short rod engine which puts extra stresses on the cylinder walls and the crank.

However, the 340/350 crank will fit in your 300 block just fine after the mains are cut down and makes a very fine engine that only weighs about 50lbs more than the Rover. The iron block handles the extra power much better and the MGB won't be affected by the weight.

Why build a Dixie cup when you can just as easily do an endurance motor?


Carl Floyd
Kingsport, TN
(3728 posts)

10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Buick 300 / rover build
Posted by: MGBV8
Date: July 27, 2019 11:17AM

I would offset grind the Rover 4.6 crank vs using the 300 crank, if you are after more stroke & want to use a Rover block.

Like Jim said, using the 300 iron block is better

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