short block options for 86
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Instructor
Joined: Jun 2014
Posts: 134
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short block options for 86
Pulled my engine last night to do a build up on the top end and freshn up the bottom and found that it isn't the stock bottom end. It's a 2bolt 87+ block (drilled for roller) it has powdered rods and DISHED pistons... So I want to get back to where it is worthy of a build up for hpde/autoX, no daily driving.
Thread Starter
Instructor
Joined: Jun 2014
Posts: 134
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Limited budget build.
I have a gm reman short block short block installed 40k miles ago at a dealer but it is the 880 casting 2bolt main roller motor with low compression pistons (dished 12cc/w 4 valve reliefs. (they cheaped out it seems) I think it's bored .020"
But need a better set of calipers at min...
#1Everything looks great about it. Still has cross hatching in cylinders.
Question is do I just build up and expect .5 - 1.0 less compression that I wanted to have and know what I got?
Or
#2 have a 880 4bolt main (from a 3500 running truck w 200k miles) worked and get a eagle rotating assembly (it will be re-balance locally) with proper pistons (yielding a 10.5:1after build)
This set up is going to cost $1300.
Or
#3buy a ATK flat top short block that is claimed to be build able to 450 with a warranty for $1400
I know what I want to do... But that option is almost 3k...
I have a gm reman short block short block installed 40k miles ago at a dealer but it is the 880 casting 2bolt main roller motor with low compression pistons (dished 12cc/w 4 valve reliefs. (they cheaped out it seems) I think it's bored .020"
But need a better set of calipers at min...
#1Everything looks great about it. Still has cross hatching in cylinders.
Question is do I just build up and expect .5 - 1.0 less compression that I wanted to have and know what I got?
Or
#2 have a 880 4bolt main (from a 3500 running truck w 200k miles) worked and get a eagle rotating assembly (it will be re-balance locally) with proper pistons (yielding a 10.5:1after build)
This set up is going to cost $1300.
Or
#3buy a ATK flat top short block that is claimed to be build able to 450 with a warranty for $1400
I know what I want to do... But that option is almost 3k...
Safety Car
Joined: Sep 2001
Posts: 4,154
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From: Glenbeulah Wi
Pulled my engine last night to do a build up on the top end and freshn up the bottom and found that it isn't the stock bottom end. It's a 2bolt 87+ block (drilled for roller) it has powdered rods and DISHED pistons... So I want to get back to where it is worthy of a build up for hpde/autoX, no daily driving.
Team Owner
Joined: Sep 2003
Posts: 25,376
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I'll agree here - I'd think there's no need to dig more deeply into the pocket. The .020+ on the bore no big deal BUT maybe the crank and rod journals are assembled with maybe something less desirable.
Thread Starter
Instructor
Joined: Jun 2014
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Is there a way to tell anything about the crank in terms of casting #s ?
I know the rods are the better lt1 powdered rods . but as you said the crank don't look anything special.
So I'm thinking get a good set of pistons and have the rotating assembly balanced for 250.
Need to get a Mike and check the cylinders so I get the correct size.
I can get a OE style piston set for 400.
I know the rods are the better lt1 powdered rods . but as you said the crank don't look anything special.
So I'm thinking get a good set of pistons and have the rotating assembly balanced for 250.
Need to get a Mike and check the cylinders so I get the correct size.
I can get a OE style piston set for 400.
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
You might take the GM short block to your machinist and have them check everything. Can't hurt to have the crank magnafluxed to make sure it's in good condition. Most short blocks will use a cast crank and they do work if you don't go too high in HP. Forged cranks can cost lots so going in that direction can easily kill the budget. An .030 bore will give you 355 cid. If you are going with new pistons, then definitely go to the .030 size. Have the shop check the rods too. There are a lot of good piston sets out there but whatever you get, have the machine shop balance the rotating assembly. A good machine shop will do a line bore for the crank and check deck height.
What heads are you going to use? Cam?
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Thread Starter
Instructor
Joined: Jun 2014
Posts: 134
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Build details :
Afr200 heads
Ti retainers \caps
Heads cleared to 600 lift
2.02/1.60 valves (3angle)
.015 intake gasket (fel1094)
Lt1 converted intake
Comp xe274h (flat tap)
Rhodes street hydraulic lifters
1.6 full roller rockers
28psi injectors
After break in of cam on stock tune car I'm going to a megasquirt pro3 ecu.
Afr200 heads
Ti retainers \caps
Heads cleared to 600 lift
2.02/1.60 valves (3angle)
.015 intake gasket (fel1094)
Lt1 converted intake
Comp xe274h (flat tap)
Rhodes street hydraulic lifters
1.6 full roller rockers
28psi injectors
After break in of cam on stock tune car I'm going to a megasquirt pro3 ecu.
Pro
Joined: Dec 2014
Posts: 530
Likes: 10
I'd swap the pistons in your current block out for some flat tops but if the crank and rods look O.K. I'd keep them. If you are concerned about needing a 4 bolt block I'd suggest having your block drilled for a set of 4 bolt splayed steel caps. You'd have a block stronger than a factory 4 bolt with nodular iron caps then.
http://www.ebay.com/itm/Chevy-SBC-350-OEM-4-Bolt-Replacement-Billet-Steel-Main-Caps-Middle-3-Caps-/171606915855?hash=item27f491bb0f&vxp=mtr
Very inexpensive peace of mind.
http://www.ebay.com/itm/Chevy-SBC-350-OEM-4-Bolt-Replacement-Billet-Steel-Main-Caps-Middle-3-Caps-/171606915855?hash=item27f491bb0f&vxp=mtr
Very inexpensive peace of mind.