Well, I just got my 454. Casting number is 10114182 and from what I've found I guess that makes this a Mark V 4 bolt main block. Have yet to check the heads. Swap will begin when I get my flywheel and clutch. Will post pictures throughout the process.

Very nice, post pics as soon as you can man....


-Rob

Will do, I can't wait until I get this baby in and fired up for the first time.

nice to see another 3rd gen doing a BBC swap. hopefully i will have mine done by spring/summer. i also got a 454 4 bolt block. Is yours needing to be rebuilt and also are you using the stock heads? i got a set of world merlin III heads that im gonna use on mine. well good look and by the sound of it you will have yours done way before mine so keep us posted.

The engine does not need a rebuild at this time. I am going to be using the stock heads until I get some more money together. But first things first. I need to get my clutch and flywheel. What do you guys think I'll run in the 1/4 (or what could it run just the way they motor is).

Did you know that's a tall-deck block?

I'm not sure of the differences, but Mark V and the more common Mark IV have incompatibilities.

You might have bit into more issues than you realize.

What are some problems that I might run into?

One-piece rear main seal for starters. No mechanical fuel pump mount boss (I believe).

If it is tall block (not sure about that - mortec.com doesn't say for sure), you need special intake manifold.

Makes the engine wider, making space a premium in a 3rd gen.

I have a Mark V in my 91 454SS pickup truck. I'm glad they were a short lived series. Probably the worst designed BBC. To my knowledge, there are no tall deck Mark V engines. Only the old 366 and 427 blocks (6.0L and 7.0L) were available in tall deck form. There are no factory 454 tall decks.

It does have some good features.
One piece rear main seal
Steel crank
4 bolt mains
Cast rocker covers with a rubber seal

It also has many bad features
Comes with peanut port heads. 3/8" rocker studs and a non adjustable valve train.
Gen IV heads don't fit without a proper head gasket or coolant will leak into the crankcase.
No fuel pump boss if you want to run a mechanical pump.
Practically no performance parts for this block.
The TBI system can't have bigger injectors installed. They're as big as they get.
Because of the peanut port heads, there are no direct swap intake manifolds.
Came with 7.9:1 compression pistons to pass emission laws but at least it will run on low octane pump gas.

Factory engine is rated at 250-260HP
NHRA CT/SA rating is 310 HP

Ouch... Well, I pulled the valve cover, and the heads are 10114156 ( 118cc Oval port heads) From what I'ved found, they're crap heads. I guess I'll be in need of some different heads then.

I read somewhere about an adapter that can be used to allow the use of mark iv heads on the mark v block. But I can't find the adapter anywhere. Is this plausible?

What's the maximum lift for those heads??

mortec.com was down when I first searched for the block casting #. One site that came up on Google said it was tall deck. I'll concede it isn't a tall deck, but the rest of your info confirmed it probably isn't a good place to start.

Stock camshaft is around .460. Aftermarket bolt in cams designed to work with the computer go up to .503 but even then they recommend changing the rockers to adjustable versions. BBC rockers use a 7/16" stud. The Gen V uses a 3/6" stud. You need conversion rocker studs that have a 3/8" base that goes into the head and a 7/16" top for the rockers. There's a special part number for these rocker studs designed just for the Gen V head. The peanut port heads (very small oval) are not even considered performance heads. Not worth investing any kind of money into.

That block casting is the same as what's in my 91 454SS truck.

Alrighty... well about how much torque should my engine have right now? I also found a decent intake that should fit the gen v for around 160.

I can't remember if I ever figured out the torque of my engine. I remember 400# but can't remember if that was with or without NOS.

My 4600 pound 91 454SS runs low 15's at about 87 MPH when racing at altitude. With NOS right off the line, it ran 13.2 at 101 MPH. 4600 pounds is a lot of weight to get moving. Aftermarket camshaft, AFPR and Edelbrock stainless headers is the only thing done to the engine. The engine still has the factory TBI although I replaced the injectors a couple of years ago. The engine only peaks out at 5500 rpm.

So what do you think I should run, mid 13's?

Depends on the vehicle's weight.

Best "corrected" HP I got from my truck engine worked out to 307.55 HP. That got me something like a 14.9 second 1/4 mile.

That much HP pushing 3200 pounds of weight should run 13.2

Will this intake fit?? http://store.summitracing.com/partde...2&autoview=sku

According to their applications listing it will but I know the intake ports won't be the same. Using a standard oval port intake gasket will work. BBC oval ports are bigger than the Gen V peanut ports.

The scary part of how much HP my truck engine produces and how slow it runs is that under the NHRA CT/SA listing which my truck would fall under, the CT/SA index means the truck should run high 11's. I'm not sure what the shipping weight is but I would need a lot more than just a weight reduction to go that fast. The massively heavy and power robbing 4L80E transmission doesn't help.

What size clutch will I be able to use?? Summit doesn't sell anything less than a 12 in. for the Mark V, that I can find.

Will I still be able to use an 11 inch clutch, and if so, where can I find one for under $300?

Or would I be better of just ditching my crap saginaw and to simplify things just go with a built 700r4??

Well the 700r4 is ordered and on the way. What did you mean about running a proper head gasket to use mark IV heads? What part number?? Reliable?