Vortecs again....Newbie
03-18-2004, 12:39 PM
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Vortecs again....Newbie
I have an 82' 355 with a Lunati Bracket Master 2 cam. Its a 292 cam with .480 lift on intake and exh. What would I have to do to a set of cast L31 Vortec heads to make them work with this cam? Thanks
03-18-2004, 02:10 PM
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Car: 86 firebird with 98 firebird interi
Engine: pump gas 427sbc Dart Lil M 13.5:1
Transmission: Oldani TH400 w/ BTE 9" convertor
Axle/Gears: 31 spline Moser/full spool/4.11Rich
I dont have all my stuff in front of me, but I think with our cam we can just bolt on the stock heads, check clearances and go-just need self aligning rockers or get screw in studs and guide plates to use old style rockers. Might be a good investment to upgrade springs to aliveate float. I had the whole vortec top end which I sold a month later for some AFR's, but defiately invest in the .015 Fel-Pro head gaskets, worth .5 bump in compression.
03-18-2004, 02:15 PM
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Car: 91 RS, 00 TA Ram Air, 86 IROC
Engine: 305 tbi, LS1, 355
Transmission: 700R4, 4L60E, 700R4 NonLU
With .480 lift you won't have a problem. Just bolt 'em on and go.
03-18-2004, 02:28 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Yeah, you can always replace the bent pushrods later.
Pull the heads apart and check guide-to-retainer clearance. Per http://www.sdpc2000.com/cart.asp?act...art&catid=2172 , "Stock ... out of the box Vortec heads ... are good for about 0.450" lift." You need about .060" more than your at-the-valve lift. While you're at it, trash those truck valve springs and put real springs and retainers on there. Might as well cut the guides for positive-type stem seals. Ever heard of a press-in rocker stud pulling out? Hmmm, might want to consider conversion to screw-in while you've got them apart.
SDPC sells Vortecs with the above mods already performed, good to ~.525-.550" lift (although it's not clear they do the screw-in studs). $700/pr.
If you insist on going with Vortecs, that is...
Pull the heads apart and check guide-to-retainer clearance. Per http://www.sdpc2000.com/cart.asp?act...art&catid=2172 , "Stock ... out of the box Vortec heads ... are good for about 0.450" lift." You need about .060" more than your at-the-valve lift. While you're at it, trash those truck valve springs and put real springs and retainers on there. Might as well cut the guides for positive-type stem seals. Ever heard of a press-in rocker stud pulling out? Hmmm, might want to consider conversion to screw-in while you've got them apart.
SDPC sells Vortecs with the above mods already performed, good to ~.525-.550" lift (although it's not clear they do the screw-in studs). $700/pr.
If you insist on going with Vortecs, that is...
03-18-2004, 02:31 PM
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Car: 86 firebird with 98 firebird interi
Engine: pump gas 427sbc Dart Lil M 13.5:1
Transmission: Oldani TH400 w/ BTE 9" convertor
Axle/Gears: 31 spline Moser/full spool/4.11Rich
Thanks for the heads up, could'nt remember exact specs they were good for out of box.
03-18-2004, 04:20 PM
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Car: '89 IROC-Z
Engine: Canfield 195 headed 358ci
Transmission: TH350, Art Carr 9.5"
Axle/Gears: 3.92 Dana 44
When I measured my vortecs there was something like .550 clearance between the valve guides and retainer. However, the factory junk valve springs need to go either way.
03-18-2004, 07:23 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by 88IROC350TPI
When I measured my vortecs there was something like .550 clearance between the valve guides and retainer. However, the factory junk valve springs need to go either way.
When I measured my vortecs there was something like .550 clearance between the valve guides and retainer. However, the factory junk valve springs need to go either way.
But, you still need to check them all. Not just one. All of them.
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