5.9 rebuild for 700hp. 12v or 24v?

[mathews8pt]

I know 700hp isnt anything too exciting in the way of a cummins build but I've never personally done one so i have a few questions.

I cracked my 53 block and have found a running '98 12v engine. Its out of a fedex truck so im assuming high mileage(not sure exactly yet) but should have had decent maintenance. I need the crank sensor to work so i have 2 options as i see it.

1. Do a leakdown/compression test and if it looks good i could just put my 24v crank in with new bearings and leave the rest be. That would be easy enough, but im not sure how much airflow id lose going to the 12v head. Spending a bunch on a P&P isnt really an option. Id need new injectors, valve springs and possibly cam(does a 24v cam work in a 12v?).

2. Have the block honed and checked out. Use my 24v rotating assembly with new rings and bearings. Possibly balance the rotating assy. O-ring the head and use new cummins head bolts. I already have a cam and valve springs so this is probably the best option really.

This is my daily driver that i will take to the track a few times a year. Im likely going to be about the same hp im at now(600) for a while longer, but figured a 600-700hp build would be the same. I wont turn much over 4k, and not often if i do.

Opinions?

 

[9724VF350]

Some late 12V engines were sill 53 blocks. Might wanna double check that.

 

[mathews8pt]

Some late 12V engines were sill 53 blocks. Might wanna double check that.

Yea i will double check that.

2 buddies bought engines from the same place/guy and their blocks just have a 5 along with some smaller #s stamped where my 53 is. The engine is rated @ 175hp, guessing thats just because it was in a fedex truck though.

 

[j-rod]

1. Do a leakdown/compression test and if it looks good i could just put my 24v crank in with new bearings and leave the rest be. That would be easy enough, but im not sure how much airflow id lose going to the 12v head. Spending a bunch on a P&P isnt really an option. Id need new injectors, valve springs and possibly cam(does a 24v cam work in a 12v?).

2. Have the block honed and checked out. Use my 24v rotating assembly with new rings and bearings. Possibly balance the rotating assy. O-ring the head and use new cummins head bolts. I already have a cam and valve springs so this is probably the best option really.

This is my daily driver that i will take to the track a few times a year. Im likely going to be about the same hp im at now(600) for a while longer, but figured a 600-700hp build would be the same. I wont turn much over 4k, and not often if i do.

Opinions?

As far as airflow, the 12v guys seem to hit a wall somewhere between 500 and 600hp with singles (arguable I guess). Twins would get you there without head work, but the stock 24v head will flow more than a stock 12v head so there would be a slight advantage at that power level.

The 24v cam has a little more lift at the lobe than the 12v cam, but you can use it.

From a cost perspective, it sounds like #2 is the cheaper and easier route.