Hi i was just wondering how many miles people where getting out of there 408's, with and with out nitrous. I was talking to a friend of mine, and he was telling me that 408 was a bad route especially for a nitrous car because the pistons come to far down and actually push on the sidewalls going up. Causing loss of power and added wear to the side skirts of the pistons. He suggested that i use stock stroke and larger bore and basically just rev the motor higher to get the power i was looking for. Now i have looks up the results from 408's on the bored and they seem to make great power which confuses me.

 

with a 4" stroke you shouldn't have any issues. maybe at 4.1" or so it might start becoming more of an issue but the ring stack would be more of a concern imo.

 

Just curious how high did you rev your 408.

 

good question. subscribing

 

I mean i understand if ls1's had a toller deck but the 6l block just dosnt add up right

 

people have been running 408s for along time and go plenty fast.

 

That's not my question how long do they last I mean i have dne enough research to know they can make power but how long do they last,

 

1 month to 5 years, Its a matter of maintance that will keep a motor alive. Not to menton a good builder and so on.

 

Well "'my buddy is dennis faerman" he has built several motors. I wanted to build a 408 origanlly but he said no way. Is why I'm asking

 

You want it to last as long as a stocker? buy a crate LS3. The 408 will last as long as any other "PERFORMANCE" engine. is this your daily driver (only car)?

 

They will last just as long as any properly maintained engine if it is built/balanced correctly.

 

There's more then just maintence, to keep the motor running long. I understand a performance motor won't last like a stock one and of course you have to maintain it properly but let's say a year or two from now when I decide to freshin up the rings and Bearings I don't want to pull my engine apart and find extra ware on my pistions and cylinder walls. Forged internals arnt cheap....

 

On the contrary, I've got about 700 to 800 bucks in forged rods and pistons. There are some good deals out there. Machine work is where it will get you.

 

You're talking about R/S ratio. This measures about 1.53:1 on a 408 or a 383. All stroker engines have that increased stress or decreased R/S ratio. There are car manufacturers that produce engines with the R/S ratio in this range, although according to one website, can't remember which, but 1.75:1 is ideal. Stock is about 1.7:1.

So take that for what its worth, and remember there are some car manufacturers that issue that ratio for stock, so it can't be that bad...

 

I know plenty of guys with lots of miles on their 408s, boosted, sprayed, and N/A. If it's built correctly and properly maintain, it will last a while.

 

I see, I figured it couldn't be too bad cause I know a ton of people run 408's. My machinest has been a family friend for years so I know he just wants wats best for me. But if u look at just about all the exotic cars they usualy use a small stroke and high rev's. Yes it might lose some low end torque but leas stroke and a higher reving motor I would think it would make just as much or more then a stroker.

 

That depends on what you're making

 

If you use good quality forged crank, rods, and pistons, then use ARP rod bolts and steel top rings, I would not be afraid of a 200 shot of nitrous. It'll hold up better than stock.

 

I know Dennis as well and he is a great engine builder. He hasn't done tons of these so is probably being cautious but we have 408s now that were built 8 years ago still running great with over 75K miles on several and making 500 RWHP so they seem to hold up just fine. We use Wiseco which have a Skirt made for this app and Diamond as well and have not had any issues at all. I can sell you or him some if he wants a piston that is known to be issue free.

I think he used to use a lot of JE and some of all the rest but I don't like their pistons at all for an LSx 408 so far even though they are a great company. The skirt they were using just had way too much rock and didn'yt work well at all as far as the last ones we saw. With the Wiseco or Diamonds he and you will be fine.