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Discussion Starter · #1 · (Edited)
Hello everyone, I recently just got a military 6.2 diesel that is a 660 block it has a few cracks in the main webbing but that’s about it I plan on having splayed main caps installed possibly and custom 18 to 1 compression pistons made. I was wondering if I put a holset hx35 on it how much power could I make reliably for driving on the street compared to a stock 6.2 with a banks sidewinder kit? I’m not looking to make crazy power by any means I plan on just lowered the compression so when I do turbo it I’m not adding cylinder pressure to the 21 to 1 compression as much. Furthermore would a 6.2 with 18 to 1 compression resemble a 6.5 diesel with 18 to 1 compression because I see those engines putting out decent power with a mechanical injection pump.
thanks for the help!
 

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I would start reading in the performance section.

 
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Discussion Starter · #4 ·
I would start reading in the performance section.

I have tried reading those and I know my question as hard to answer but I’m just trying to figure out if I lower the compression to 18 to 1 would it resemble a 6.5 diesel with 18 to 1 compression because I see those engines putting out decent power.
 

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Lower compression alone won't gain power, it will allow room for more fuel and air with lower cylinder pressure.. that is where more power comes from..
 

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Discussion Starter · #6 ·
Lower compression alone won't gain power, it will allow room for more fuel and air with lower cylinder pressure.. that is where more power comes from..
I know lowering the compression won’t add power alone I plan on running a turbo and an intercooler and turning up the injection pump, i’m just wondering if it would resemble a 6.5 with 18 to 1 compression in someway.
 

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I havent heard anything good about splayed main caps. Someone was saying they weren't very good around here not long ago. I would probably not build a block with more than one main web crack though personally. If you do, add studs and a girdle.

As for power, my guess is you're looking at 210hp/350tq. Total guess and butt dyno of my old 6.2 with an HX35 compared to a TBI big block. They can be made pretty reliable with an HX35. I really liked mine.
 
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Discussion Starter · #8 ·
I havent heard anything good about splayed main caps. Someone was saying they weren't very good around here not long ago. I would probably not build a block with more than one main web crack though personally. If you do, add studs and a girdle.

As for power, my guess is you're looking at 210hp/350tq. Total guess and butt dyno of my old 6.2 with an HX35 compared to a TBI big block. They can be made pretty reliable with an HX35. I really liked mine.
That’s pretty decent power for that engine. I’ve been trying to look around for a crack for a block but I’m not sure where to look I also was talking to somebody who was a machinist and worked on 6.2 and 6.5’s and he said he’s never had people come back and say it didn’t work. Splayed main carbs are one of those things you hear good reviews and bad reviews equally.
 

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Only place to look is another engine lol! I went through a handful to get a good one. As for the splayed caps, I wouldnt put that kind of effort into a 6.2 personally. I'd run some main studs, maybe a girdle, and send it.
 
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Discussion Starter · #10 ·
Only place to look is another engine lol! I went through a handful to get a good one. As for the splayed caps, I wouldnt put that kind of effort into a 6.2 personally. I'd run some main studs, maybe a girdle, and send it.
OK I’ll keep that in mind! Thanks
 

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Discussion Starter · #11 ·
Only place to look is another engine lol! I went through a handful to get a good one. As for the splayed caps, I wouldnt put that kind of effort into a 6.2 personally. I'd run some main studs, maybe a girdle, and send it.
Should I keep going for surplus 6.2 to find a good one because they have low miles or should I go for a high mileage 6.2?
 

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Honestly, I never wanted to pay surplus 6.2 prices. Chances though are they are solid. I just kept grabbing them off craigslist. Hell, the last one I bought for 50 bucks. That was the most worn out turd but it hauled that truck around for almost 5 years. It really liked Delo 😅 Nothing wrong with paying a few extra bucks for a nice one. Also nothing wrong with going on the cheap engine hunt.
 
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