8.1L swap into my 7.4L K2500 Burb

[grampadirt]

Think I know the answer but I would guess a tbi cannot supply enough fuel to feed that 502,true?Sorry for the thread jack.

 

[David Cruz]

Think I know the answer but I would guess a tbi cannot supply enough fuel to feed that 502,true?

Something like that, I could get a ported TBI unit that flows around 720cfm and mess with getting chip flashing equipment, but for the money a new street demon for now.

 

[Mildphil]

Does anyone know if the heads off an 8.1 would swap onto a 7.4 vortec? Just curious since the the 8100 has those nice roller rockers. Looks like it has a one piece Intake manifold too.

 

[L31MaxExpress]

Does anyone know if the heads off an 8.1 would swap onto a 7.4 vortec? Just curious since the the 8100 has those nice roller rockers. Looks like it has a one piece Intake manifold too.

A stock 8.1 does not have roller rockers.

 

[Christian Steffen]

Does anyone know if the heads off an 8.1 would swap onto a 7.4 vortec? Just curious since the the 8100 has those nice roller rockers. Looks like it has a one piece Intake manifold too.

Well from what i read normal big block heads won't fit the 8.1, so i'd assume no to this.

 

[L31MaxExpress]

Well from what i read normal big block heads won't fit the 8.1, so i'd assume no to this.

That is correct. The head bolt pattern is not the same. I have seen a few 8.1 builds where the block was modified to use older heads but it involves some machine work. Capping off a bolt hole with threaded iron plugs, redrilling a hole, tapping it and a resurface.

 

[Schurkey]

THREE head bolt holes on each deck need to be moved to swap heads between the older big-blocks and the 8.1L. Six holes per engine block.

The holes need to be moved about 1/2 of their diameter. See the pen/pencil points where I've laid the older gasket on top of an 8,1L gasket.

There's coolant-passage changes also.

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