bluedawg

On racingjunk.com there is a main girdle for sale, don't know how much it would help strengthen a two bolt block. If it were me I'd still go four bolt.

Nobody.

Here's some good reading if you have time. This guy took a 100K mile 350 with cast crank, stock rods, and .040" over replacement cast pistons in a 2-bolt block and made RELIABLE 700+ RWHP in a twin-turbo application. Stock main bolts, etc. Thousands of street miles and hundreds of 1/4 mile runs mostly in the 9's. Car Craft magazine did a write-up about it and it's no BS:

http://www.theturboforums.com/smf/th...art-2-to-come/

yellow 72

Original numbers matching 30 over 350 block, est 500 hp...2 bolt mains with ARP studs.....so far all rotating parts are still where I originally put em.

Indiancreek

Here is the problem with the pistons first, then bore and hone a seasoned block. They don't all end up 0.030 or whatever size. Then the customer is standing there with 8 pistons 0.030 and holes at 0.040 or more. I bore the holes then recomend the piston purchase. There are times when It takes the hone to clean up the last eyebrows. Only reason I see for wanting the rings would be to end gap them.

L88Plus

Forced induction is another ballgame altogether. I asked a machinist friend why power capacities were so much more with a turbo or supercharger. His comment was that the FI "cushions" the engine and levels out the harmonics/impacts of individual cylinder firings. I saw a chart somewhere that gave "factors" to be used with forced induction versus N/A. Cast cranks, multiply N/A capacity by 1.5, etc.

High revs and detonation are the enemy of 2-bolt blocks, stay out of either and you could probably make some insane power.

Steve2147

Yes, that's what I thought. I don't know why you'd need them to bore and hone. i always did end gaps when I was ready to hang the rings.

Steve g

billla

We may be looking at this from two perspectives - shop and builder. I'm not suggesting anyone buy pistons and then see what the block will clean up at

A very simplified version of the process I follow is:

1. I teardown and inspect, and do initial measurements and block prep.

2. My shop cleans, mags, pressure tests and measures the block. We agree on machine operations based on measurements, usage, budget, etc.

3. I order parts based on what we agreed to.

4. The machine operations are completed.

5. I do final measures, checks, mock-up as required and final assembly (including gapping the rings ).

Unless there's damage to or pitting of the bore, the initial measurements and sonic will determine what the bore will clean up at. For classic engines, I'll sometimes order classic pistons that are "like P/N nnnn, but based on a .0nn bore", or "high limit" pistons that are maybe .005 oversize. Lots of options any more

So if a guy shows up with a cheap "rebuilder" kit with cast pistons and rings, and another guy shows up with forged pistons and thin, chrome rings...they both get exactly the same final hone?

All good discussion, but we digress from the OP's topic which has also had a lot of good discussion I think we can agree that the right answer here is to be an informed consumer of machine shop services, and work closely with your machine shop BEFORE any parts are bought to ensure you're both on the same page. Fair?

If this needs more coverage, then someone can start a new thread

Indiancreek

Can't explain that. Cardinal rule here is don't buy you pistons until I bore the block. I have two sitting out there now with pistons bought before the bore and they just are not going to clean up. The deal is now the owner having to try to return and exchange them or buy another set and put the first set on e-bay.
Only time I want the pistons is for a set of used pistons.
The problem with measuring the cylinders is the measurement is from side to side. That is one measurement. Unfortunatly, when the cylinder is bored it is relationship to a cylinder perpendicular to the deck. So the measurement would have to be from the true cylinder not just from side to side of the existing cylinder. I suspect that all came out as clear as mud, but the exsisting cylinder is worn at an angle that isn't true to the deck.
If that didn't come across well I apologize.