james_fearn

Is this a good starting point for a build up? are the pistons decent? Any thoughts/experience with it???

I'm looking for a mild and effiecient 350 buildup for the summer time frame complete w/ zz4 cam and TFS 23* heads.


James

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1985 Z-28 305 TPI
221,000+ mi., Original Eng.

rangelec

I have an L31 in my 86 Z28. The stock pistons are cast and with the stock heads are 9.4:1 comp. The stock vortec heads are very good up to .480 lift and beyond if you change springs. I am using the GM hotcam kit in mine-about 410 hp,430 ft-lbs tq-750 carb, etc. The block is a roller cam block also. The light duty block (1500 pickup) is two bolt main. The medium duty(2500-3500 pickup) is four bolt main. I believe the rods are the PM type with a cast crank-good for 6000 rpm. Mine runs great.

Kevin91Z

iTrader: (1)

L31 is Vortec? I have a 96 Vortec block in my car. The pistons are hyperuetectic. Aside from having to replace the timing cover with a regular one, and get a fuel pump block off plate, everyone was fine.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

Abird4u2nv1

iTrader: (-1)

Kevin, did you have to do anything to put that normal timing cover on? I've heard something about drilling a hole or 2 for the timing cover. Also, anyone know anything about the crank on these? I have an L31 stripped bare, the crank was ate up by a spun bearing, and it had a crank sensor with a reluctor plate on the crank. Can I just stick any normal 350 1 piece rear crank in it?

Rob Wade

I bought a new L31 shortblock from summit for 1499.00. It is a 4 bolt roller block, cast crank, PM rods and cast -13 cc dish w/ 4 relief pistons. I added trickflow heads, edelbrock intake/runners, #24 injectors, stock L98 cam w/ 106 rr's. The correct GM roller chain and 16 new gm roller lifters. Mellings oil pump and arp steel oil pump shaft with complete gasket kit. Cost $4000.00 total @ summit. I added a 52mm TB and ported the plenum. I am still running the stock prom and I am reasonably happy with good performance and very good fuel economy ( my reason for the stock cam). Pulls very hard down low, even in a 4000 Jag w/ a 2:88 gear. I will get it tuned next spring.