[zachscc]

I have a 427 steel crank out of a truck I think the guy told me I know it is a steel and not cast because my machine shop buddy told me it has the thick weld line on the front counter weight as oppossed to the more common thin Welded line. Is this correct? The guy that I bought it from years ago said the gear drive pully on the front snout was from a factory gear drive?
Anyway, my question is what kind of block do I want to look for to build my dream 8000 RPM Big Block 427 for my 69 Chevelle? I have been told that all I need to do is find a 2 Bolt 454 block (put in spalyed 4 bolt maincaps) and then put in the 427 Crank and 396/427 rods with 427 pistons ovcoarse and I will have a destroked internally balenced 454 with 427 CID. Does it matter if I find a block from a truck or a car (I am planning on buying Aluminum heads) so heads really don't matter, what years should I look for and what year blocks should I avoid? Thanks in advance for any info my fellow gearhead bretheren. Zach <img src="graemlins/pimp.gif" border="0" alt="[pimp]" />

[BOBCRMAN@aol.com]

the truck crank is a forging, with the combo you suggested you will in fact have a 427, blocks are available from 68 on. You will need a markIV block, two or four bolt won't really matter, the truck blocks are .400" taller and require a spacer for the intake and a different distributor for auto use also longer rods. you will have to check block numbers as quite a few 396's have been bored to 427 size, this is ok for early four bolts but some two bolts can't handle the overbore. check the front of the block around the cam bearing for timing gear wear, make sure the main caps fit tight side to side in the block. Don't try to use late style heads on early blocks, lots of head styles and chamber sizes are available, always replace the valves and springs with quality new ones (big blocks will drop or break valves), always use the best rod bolts. Big blocks are very durable but heavy make lots of torque.

[zachscc]

Thanks Bob! Once again your info helps alot. Does anyone know if I can have a Mark IV truck block Decked to remove that .400 " Difference and avoid having to find a different distributer as well as rods?

[Super Streeter]

There is no such thing as a tall deck 454.Only 366's and 427's were tall decks and only in big straight job type trucks.All pickup trucks and boats as well as cars had 454's and are low deck.If you have a bigblock out of a schoolbus or dump truck,it is usually a 366 and a tall deck.As for the 427,you will have the same engine as me.I run a 2 bolt main 454 block with a 396 crank in it.I only have main studs,not 4 bolt caps.I run it to 7500rpm and make 650 horsepower on motor and add another 400 in nitrous,so I total about 1050 horsepower with 2 bolt caps.I had to Oring the decks for copper head gaskets because the head gaskets would blow out but te main caps held up fine.I only built the 427{actually bored to 440 inches}because I wanted to race a class that made the smaller motor more desirable,I would have built it as a 468 or even a 496 if I wasnt restricted at the time.Good luck.

[zachscc]

Thanks super, I asume that main studs are stronger than stock bolts? I assume with a 496 I would have to buy externally balanced crank, balencer and flywheel and it would not rap as high or as fast is that correct? Or do you think the added power outwieghs the external balence problem? Did you blow the head gaskets from compression or from the NOS? What kind of Aluminum heads do you recomend? I want to run a hydrolic roller cam so it will still be streetable (on ocasional nice sunny days anyway).

[Super Streeter]

Externally balancing isnt a problem at all,and I wouldnt go out of my way to internally balance an engine.As for studs,they might be a little stronger then bolts.If nothing else,you arent beating up the threads in a 30 year old block every time you run the bolts in and out.
I was runing GM cast iron heads when I built it,and the decks of the heads were kind of thin,so the head gaskets were leaving black tracks from the top of the cyliners into the lifter valley area,so I knew gasket sealing was marginal.I had a problem with one of the heads being cracked,so I replaced them with a set of new GM aluminum rectangular port heads.These heads as well as their oval port versions are both the best deal on the market for bigblock aluminum heads.For a 6000rpm 427 I recommend the oval port version{actually the same heads that come on a ZZ502 crate motor}while for a 6000 rpm 496,I would run the rectangualr ports.Both cost about the same in fully assembled form,and come with springs that work with most hydraulic roller cams with under .600" lift.I ran the rectangular heads on my 427,but it spins over 7000rpm,and has a 5000 stall convertor.On the 427,you would have a good combo with the oval port heads,and RPM airgap intake,800 cfm carb,and about 10:1 compression.A hydraulic roller with about 235 degrees duration at .050" and .550" lift would work well with this setup.Good luck and let us know what you choose.

[willy77]

Your best bet is to use main studs because of the clamping action and more accurate torque!
Nothing beats a Stud. ARP with rolled threads check out ARP website. Good luck <img src="graemlins/crash.gif" border="0" alt="[crash]" />

[deuce_454]

you want a blok with 512 as the last casting digits. its the thickwalled (can be safely bored .125 over) and has 4 bolt mains.

[Super Streeter]

A #289 block from 72 thru 79 will usually sonic the same as the 512's and they are much more common.But the 512 is still a good piece.

[zachscc]

Are the 454 blocks that end in 289 2 Bolt blocks?

[zachscc]

I have heard that in destroking a 454 to 427 as I have been planning I will have to deal with the same type of clearance issues that you do when you build a 383 small block stroker is this the case? Did you have to worry about rod clearance etc..Super?I thought the only diff between 427 and 454 blocks was the 454 had notches cut in the block to accept the larger counterwiegts? <img src="confused.gif" border="0">

[Super Streeter]

You can stroke down without clearance issues,it is stroking up that causes problems.You can do a 27 out os a 454 with no problems.As for 289 blocks,most that were installed in passenger cars and trucks were 2 bolt.Maybe a Corvette block would be a 4 bolt,and they also used the 289 in service replacement L88's and LS6's and 7's after 1972,and they were all 4 bolts.