Gold Phoenix

iTrader: (1)

Well, does anyone? I saw Lunati's new 14 crank kit combos ranging from 347 to 395cid in a LS1 with compressions at 8.5,10.6, and 12:1. I thought about going to the 395 which is stock bore with a 4.125 stroke and 6.125 Rod

Chicago Crew UnderBoss

iTrader: (1)

My brand new MTI 427 Ironblock utilizes the 4.125 crank with 4.060 overbore=427.2 cubes. So far so good but i only have 325 miles on the motor. I have heard of many LS1 folk using the big crank with no problem and have also heard several say that they would not go with more than the 4.00 crank in a LS1 b/c of piston speed and rod angle but most expert SBC engine builders i interviewed told me i should be perfectly fine. However, i'm no mechanic but i do believe your piston speed and rod angle will be even more pronounced on a stock bore motor (but not positive about this).

Time will tell but i can tell you this, my BEAST is a TORQUE monster and is WICKED FAST!

I say go for it, afer you first do your homework and talk to a few experts like Jayson at MTI or WADE at ARE (who i hear is a big proponent of this big crank) etc.

MTI 427 C5 Roadster

<small>[ March 18, 2003, 09:59 PM: Message edited by: MTI 427 C5 Roadster ]</small>

Chicago Crew UnderBoss

iTrader: (1)

My brand new MTI 427 Ironblock utilizes the 4.125 crank with 4.060 overbore=427.2 cubes. So far so good but i only have 325 miles on the motor. I have heard of many LS1 folk using the big crank with no problem and have also heard several say that they would not go with more than the 4.00 crank in a LS1 b/c of piston speed and rod angle but most expert SBC engine builders i interviewed told me i should be perfectly fine.

Time will tell but i can tell you this my BEAST is TORQUE monster and is WICKED FAST!

I say go for it, afer talking to a few experts like Jayson at MTI or WADE at ARE (who i hear is a big proponent of this big crank) etc.

MTI 427 C5 Roadster

robertbartsch

Question: With the 4.125 crank and the iron LQ4 block ...did the block need to be "clearanced" ...in other words, did the block need to be shaved in spots to avoid the crank, rods, pistns from hitting the block ....it would be nice if the crank just dropped in the LQ4....

....also, i assume the rotating assembly needed to be balanced since there are currently no avialble complete kits (crank, rods, pistons, rings) for the 4" bore in the LQ4...

HITMANSS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by MTI 427 C5 Roadster:
<strong> However, i'm no mechanic but i do believe your piston speed and rod angle will be even more pronounced on a stock bore motor (but not positive about this).
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bore size has no effect on piston speed or rod angle --- it's primarily a function of stroke & rod length. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

<small>[ March 20, 2003, 08:58 AM: Message edited by: HITMANSS ]</small>

Chicago Crew UnderBoss

iTrader: (1)

ROBERTBARTSCH:

Not sure about your tech. questions that why i have to hire expert engine builder like MTI for my 427 engine build. I am sure some technogolically inclinded folk here (or for sure engine builders on the forum) can answer these tech. questions of yours.

MTI 427 C5 Roadster

427ZO6

I have and ARE 427 with 7000 miles and undtold dyno time as we attempted to resolve the belt slippage issue with the ATI SC. I just opened the motor per Wade's suggestion to take am look- see. The motor was in excellent condition. It was reassembled and pulled NA 493 RWHP and 488 RWTQ through the exhaust. When the weather clears it will get a final tune. I am expecting 510+ RWHP.

Enjoy you car and don't worry. MTI is a very reputable tuner and engine builder.