74 NovaMan's 1979 Chevy Truck - LS Swap - 5/6 Drop

[74NovaMan]

The block checked out very well. I am going to go with the .005 over pistons and hone the cylinders to fit likely under $100 (vs $480 for boring oversize). My piston choices are 7cc dish: https://www.summitracing.com/parts/sum-2999273785-7 or 2cc dome: https://www.summitracing.com/parts/sum-2999273785-2

If I use the 706 heads that I have (pressure tested good) my compression ratio is either 9.7 or 10.9 respectively.

I have a line on 317 heads from a 2008 6.0L that were removed at under 10,000 miles from new that I can get for cheap. These would be ready to run but the chamber size is 71cc (vs 61cc for the 706 heads) Compression ratio for this head is either 8.7 or 9.6 respectively. This is according to the chart from Summit:

[74NovaMan]

whatever Google tells me...

I see how you are! Making me do my own research!

Seriously, I very much appreciate your input on all of this stuff even if I end up going another direction.

[SuperBuickGuy]

Thanks for the note on ring gap. I probably would have missed that. What are you planning for your gaps?

The new rods come with ARP bolts.

whatever Google tells me...

[74NovaMan]

if you do forced induction, remember to increase the gap on your rings..... that would really bite to spend all that money then hang a ring and break a land....

oh yeah, and buy the ARP bolts

Thanks for the note on ring gap. I probably would have missed that. What are you planning for your gaps?

The new rods come with ARP bolts.

[SuperBuickGuy]

if you do forced induction, remember to increase the gap on your rings..... that would really bite to spend all that money then hang a ring and break a land....

oh yeah, and buy the ARP bolts

[74NovaMan]

like most anything, replace the rod bolts with ARP and it will be fine. If you're planning on more then 600 hp, then rods are important.... at least that seems to be the prevailing theory. If you're not planning more then 6500 rpm, you don't even need to change the bolts.

I did not heed your earlier advice/warning and went down the rabbit hole yesterday "researching" the rod/rod bolt issue. Here is my logic (FWIW):

Given that the pistons need replacing I have it broken down to 2 options.

Option 1:
Stock style oversize piston to work with my original rods are $290: https://www.summitracing.com/parts/s...make/chevrolet
These require boring the cylinders: $480
ARP rod bolts: $97
Total: $867

Option 2:
Forged pistons in either .005 over (for a hone) or .030 over (bore) $500 https://www.summitracing.com/parts/s...make/chevrolet
Boring the cylinders (worst case assumption) $480
New Rods $440 https://www.summitracing.com/parts/s...2521/overview/
Total (worst case): $1,420

The cost difference is $553. Seeing as I'm rapidly approaching $3,000 why stop short on doing it right the first time. It also sets me up nicely for forced induction or nitrous (which may never happen). If I only needed rings, I'd just slap it together and call it a day.

[74NovaMan]

I like the Scat H-beam rods in my Fords - no clue if there is any issues with them in an LS engine. As to the bore - IF (IIIIIFFFFFFF) the bores are round and straight - then honing them to size probably will be OK. If the skirts are worn, I would suspect that there could be some wear in the cylinders as well. Honing does not always square up everything and remove the taper. What does the machine shop charge to hone ($150 - $200)?

Since we are spending your money, I would put a stroker kit in it while it is apart. As someone once said - there is no replacement for displacement!

The machinist said that he would be checking the block today. If there is any question, I'll just bore it at this point. I already have the stock crank polished and ready to go, but I did consider a stroker kit for a few minutes.

[SuperBuickGuy]

like most anything, replace the rod bolts with ARP and it will be fine. If you're planning on more then 600 hp, then rods are important.... at least that seems to be the prevailing theory. If you're not planning more then 6500 rpm, you don't even need to change the bolts.

[cstmwgn]

I like the Scat H-beam rods in my Fords - no clue if there is any issues with them in an LS engine. As to the bore - IF (IIIIIFFFFFFF) the bores are round and straight - then honing them to size probably will be OK. If the skirts are worn, I would suspect that there could be some wear in the cylinders as well. Honing does not always square up everything and remove the taper. What does the machine shop charge to hone ($150 - $200)?

Since we are spending your money, I would put a stroker kit in it while it is apart. As someone once said - there is no replacement for displacement!

[74NovaMan]

Just got word that the crankshaft cleaned up with just a polish. I'll pick that up in a few days. Should be about $150 with bearings.

In other news, I've spent far too much time looking at connecting rod information and looking for piston/rod combos. My machinist has not measured anything yet but did not like the look of the piston skirts and said replacement is probably warranted. I can get .005 over forged pistons for $499.99: https://www.summitracing.com/search/...re-in/3-785-in .030 over versions are the same price but come with the need for $480 in boring the cylinders. Any of these pistons require a 6.125 inch long connecting rod (which may be a worthwhile upgrade anyway). This is a likely candidate: https://www.summitracing.com/parts/s...2521/overview/ If I believe the internet, these are a deal over new bolts and resizing the rod ends (to the extent that is even possible on the LS cracked cap rods).

There are too many variables and none of the cheap stuff makes much sense to me given the assumption of piston replacement.

[74NovaMan]

http://blog.wiseco.com/choosing-the-perfect-ls-connecting-rod-6.098in-vs-6.125in?hs_amp=true

[74NovaMan]

Planning on dropping off the block and heads at the machine shop today.

[74NovaMan]

Crank looked very good. I ran out of workbench space though.

[74NovaMan]

Rod bearings looked very good. There was some light scoring on the mains.

[74NovaMan]

Pistons came out easily (no ridge on the cylinder). All looked pretty consistent. Not sure if the scoring on the skirts is anything to be overly concerned about. I'd like to reuse the pistons and rods.