98 ls1 rebuild question?

**98goldta** · 03-21-2010, 03:50 PM

I have torn down the motor after 220k on it. all is well with the internals. I am rebuilding it based on 03 zo6 ls6 specs. cam ,valves,springs and pistons. Porting the heads and reusing the crank and rods as there is nothing wrong with them. my question is , I have read here and other ls1 sites that if I even hone the cylinders I need to get oversized pistons as the standard size will not work. is this true. I am not boring the block , just a finish hone to seat the new rings. Do I even need to hone the block for new rings. I read on another site that gm when replacing rings does not recommend honing. The problem is the 98's cant be bored and the next size up piston is .010". I would have to special order a custom forged piston and that is costly. any advice or experience on this would be great. thanks in advance

**tylerdurden1** · 03-21-2010, 10:08 PM

I not 100% sure on the over boring max, but I seen .005 over size pistons from gm. Heck with that many miles I would have to bet that the bore right now is very close to that right now. I would recommend that you find a good manchine shop in your area and drop off those parts and have them all measured out. Have the crank polished, conn rods checked.
I would recommend having the rotating assembly balanced with file fit rings and arp conn rod bolts. I know the cost factor is but have you looked into a 382 stroker kit. The bore is the same just crank, rods and piston height is different.

**Lawnboy** · 03-22-2010, 07:27 PM

OK diamond pistons are like 7 thousands over bore and i think will work in a 98 block.
The 98 block is good for one bore/hone job.

I would go with a good set of eagle , callies or scat H beams and u will have a super strong block. The stock crank is very strong and good to reuse on a budget rebuild . strock rods are ok, but i seen them fail

pistons and rods and u can boost or spray that new rebuilt motor without worry

**67CamaroRSSS** · 03-22-2010, 07:51 PM

I think your stock 98 LS1 heads (8 something or other) will choke down the cam. You will need 243 heads for it to perform like an 03 ZO6. Different heads will also need to use different valve covers and coil brackets (98 was a 1 year only setup for F-body). You'll also need an LS6 intake manifold.

**3rdgen** · 06-21-2011, 03:01 PM

98 ls1 can be honed out to a max of 3.905, which is what I'm doing at the moment.

**SSwt00SS** · 07-01-2011, 06:21 AM

Originally Posted by 67CamaroRSSS

I think your stock 98 LS1 heads (8 something or other)...

806 and 853 are perimeter bolt heads. if they are 806 get rid of them. they are worst flowing Ls1 style head.

241 and 243 are center bolt heads

**redbird555** · 07-01-2011, 07:41 AM

Originally Posted by SSwt00SS

806 and 853 are perimeter bolt heads. if they are 806 get rid of them. they are worst flowing Ls1 style head.

241 and 243 are center bolt heads

The 806 which only came on 97-98 ls1's had perimeter holes. The 853 heads made in 99-00 had center bolt holes my buddy had them on his 00 and they were center bolt.
Either way if you want it to perform up to snuff get a ported set of 241's or a set of 243 heads which are standard ls2/6 heads and go from there.

**3rdgen** · 07-01-2011, 09:25 AM

Originally Posted by SSwt00SS

806 and 853 are perimeter bolt heads. if they are 806 get rid of them. they are worst flowing Ls1 style head.

241 and 243 are center bolt heads

I really don't know why people continue to say that 806 heads have poor flow characteristics. The 806 and 241 heads are the same in all regards except for the 806's are perimeter bolts, while 241's are center bolts.

**SSwt00SS** · 07-01-2011, 09:37 AM

Originally Posted by redbird555

The 806 which only came on 97-98 ls1's had perimeter holes. The 853 heads made in 99-00 had center bolt holes my buddy had them on his 00 and they were center bolt.
Either way if you want it to perform up to snuff get a ported set of 241's or a set of 243 heads which are standard ls2/6 heads and go from there.

i stand corrected. i was under the understanding that the 8-series were perimeter. thanks for the correction.

**redbird555** · 07-01-2011, 04:17 PM

Originally Posted by 3rdgen

I really don't know why people continue to say that 806 heads have poor flow characteristics. The 806 and 241 heads are the same in all regards except for the 806's are perimeter bolts, while 241's are center bolts.

There really isnt any info to prove either way however 241 heads started using sand cast molds in 01 which in fcat created a much smoother casting surface which would lead to the idea of better flow over the older ones however I've never seen any flow data to validate this one way or another.

Originally Posted by SSwt00SS

i stand corrected. i was under the understanding that the 8-series were perimeter. thanks for the correction.

No prob everyone learns something now and then