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Post by Brett Heidgerken on Aug 9, 2005 16:46:46 GMT -5
Anybody know much about factory 502 blocks? How strong are they? Bore thickness? How far can they be bored? 4.530, 4.560, 4.600? How easy is it to put in a 4.25 stroke? Thanks.
Brett
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Post by stevehoch on Aug 9, 2005 23:20:38 GMT -5
Brett, I had my 502 overhauled this last winter and bored it to a true 4.50 bore, 13.5 comp, GM alum. heads ported and easly made 1165HP with 300 HP NOS. Borowski did the machine work and could probably tell you how far it can be bored, some clearancing is needed for 4.25 stroke but easily done. I think he recommended the merlin block if you want to make much more power but is a heavier block than GM. Hope this helps.
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Post by Kevin Neal on Aug 10, 2005 6:07:48 GMT -5
Mine is bored 4.560 and has a 4.50 crank with steel rods and only needed a little clearance. I think a 4.25 would have fit with no clearance. The biggest problem with the Bowtie blocks are the thin decks, they tend to pull threads out of the block and if bored to 4.600+ they can crack from the head bolt holoe to the bore. If you are going to make big power think about filling the block to the water pump holes.
I wouldn't be scared pf it if its something you already own, but if your buying a new block, buy a dart or a merlin.
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Post by TuffGuyRacing on Aug 11, 2005 9:23:23 GMT -5
The Gen V Gen VI 502 blocks can safely go to 4.600. No Clearancing needed with 4.250 crank and STEEL rods. You will need to clearance w/ aluminum rods. The gen V Gen VI has a thicker deck than a Mark IV Bowtie so you wont pull threads.
The Gen VI has lifter bores taller than GEN V and MK IV so you would need to machine them or use a taller lifter (Comp cams sells them)
I use Gen VI and Merlin blocks but when I buy a new one it will be a Dart
When shopping for a block, my order of preference would be:
1. DART
2. Merlin III
3. Merlin II
4. Gen VI
5. Bowtie MK IV
6. GEN V
hope this helps
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Post by TGR on Aug 11, 2005 9:26:10 GMT -5
Also if using a Gen VI block you will need to modify or machine a oil filter bypass as no one sells them as of yet
You can easily modify the stock one to make it solid or machine one. Otherwise you will be bypassing the oil filter ALL of the time.
OH, and dont forget the o-ring under the rear main cap
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Post by Brett on Aug 13, 2005 9:54:06 GMT -5
Thanks for all the good info guys.
BRett
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Post by Brian on Nov 9, 2005 6:58:49 GMT -5
forgot to mention that there are 2 bypasses - 1 under threaded nipple that oil filter goes on (dont use that one) and 1 next to the threaded nipple for oil filter - thats the one you need to "plug". If the block is bare, you can tap it 1/2" NPT and put a plug in it, if it is already assembled, you can modify (plug) stock one (not recommended) , machine a new solid one or use a 20mm or 13/16 expansion plug
You will have to buy a few of each expansion plugs to get one to fit or bring your dial caliper w/ you to find one that is roughly .804-.809
Ideally machining a solid blockoff is the way to go and tapping it to accept 1/2" plug is second
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