motor advice?

yota · 05-31-2013, 03:37 PM

I'm trying to decide what to do for the motor in my Trans Am...

LS6 346, stock crank, GRP rods, cp pistons, Trickflow 225 heads ported by tea, prc .675 springs, stock rockers with trunion upgrade, solid roller motor, billet girdle, ported oil pump, and balancer. Engine is used, but completely disassembled and will be put back together as "new" before purchase. Has been a best of 8.93@150 in the 1/4 at VMP in an LT1 body Camaro which is the current record for a 346ci LS motor on nitrous.

-or-

Iron block 408 with lunati crank and rods, wiseco pistons, comp roller rockers, trickflow 235 heads, ported oil pump, custom cam. This would be a new build, with all brand new parts and fresh machine work.

Honestly, I'm leaning more towards the 408 even though it's $2000 more than the "race proven" 346. My overall goal- which either combo will achieve I think, is 500+ on motor and about 700+ on nitrous. Trans will be a built 4l80e and rear will be a 3.90 gear 9".

Thoughts?

jmd · 06-01-2013, 05:03 AM

408!

bwelch · 06-01-2013, 05:32 AM

408

BAD BOB · 06-01-2013, 08:28 AM

id say 408 as well so you are getting all good parts in the motor and not using the stock crank in the 346, which seems a little goofy with everything else aftermarket

djfury05 · 06-01-2013, 11:14 AM

Aren't the GRP rods aluminum and not recomended for street use? Unless this is a drag only car I vote 408.

yota · 06-01-2013, 12:27 PM

Yeah, I think I'm gonna pass on the 346.

oldskoolstang · 06-02-2013, 08:07 PM

408 fo sho....

DIGGLER · 06-03-2013, 09:12 AM

how much is he selling that 346 for?

05-31-2013, 03:37 PM	#1
yota Senior Member Join Date: Jun 2011 Location: Va Posts: 1,049	motor advice? I'm trying to decide what to do for the motor in my Trans Am... LS6 346, stock crank, GRP rods, cp pistons, Trickflow 225 heads ported by tea, prc .675 springs, stock rockers with trunion upgrade, solid roller motor, billet girdle, ported oil pump, and balancer. Engine is used, but completely disassembled and will be put back together as "new" before purchase. Has been a best of 8.93@150 in the 1/4 at VMP in an LT1 body Camaro which is the current record for a 346ci LS motor on nitrous. -or- Iron block 408 with lunati crank and rods, wiseco pistons, comp roller rockers, trickflow 235 heads, ported oil pump, custom cam. This would be a new build, with all brand new parts and fresh machine work. Honestly, I'm leaning more towards the 408 even though it's $2000 more than the "race proven" 346. My overall goal- which either combo will achieve I think, is 500+ on motor and about 700+ on nitrous. Trans will be a built 4l80e and rear will be a 3.90 gear 9". Thoughts? __________________ 1999 Trans Am 2007.5 Dodge Mega Cab Cummins

06-01-2013, 05:03 AM	#2
jmd Senior Member Join Date: May 2008 Posts: 3,177	408! __________________ Cadillac man

06-01-2013, 05:32 AM	#3
bwelch Senior Member Join Date: Aug 2009 Posts: 3,774	408 __________________

06-01-2013, 08:28 AM	#4
BAD BOB Senior Member Join Date: Mar 2008 Location: SUMMERVILLE Posts: 3,681	id say 408 as well so you are getting all good parts in the motor and not using the stock crank in the 346, which seems a little goofy with everything else aftermarket __________________ IM BAD BOB

06-01-2013, 11:14 AM	#5
djfury05 Senior Member Join Date: May 2012 Location: Beaufort, SC Posts: 242	Aren't the GRP rods aluminum and not recomended for street use? Unless this is a drag only car I vote 408. __________________ C6Z

06-01-2013, 12:27 PM	#6
yota Senior Member Join Date: Jun 2011 Location: Va Posts: 1,049	Yeah, I think I'm gonna pass on the 346. __________________ 1999 Trans Am 2007.5 Dodge Mega Cab Cummins

06-02-2013, 08:07 PM	#7
oldskoolstang Senior Member Join Date: Apr 2012 Location: Guyton, GA Posts: 1,412	408 fo sho.... __________________ Working on junk....

06-03-2013, 09:12 AM	#8
DIGGLER Senior Member Join Date: Aug 2012 Posts: 1,458	how much is he selling that 346 for?