mulletwearingtadrive

iTrader: (10)

what are all the differences between an LT1 and an LT4?


also, i had a guy tell me that LT4's will ENGINE dyno at 425.....is this true?

Zepher

LT4 intake is red.
LT4 has a bigger cam
LT4 has roller rockers
LT4 has composite valve covers
LT4 has a stronger timing set
LT4 has better flowing heads and raised intake ports
LT4 with the LT4 Hot Cam is rated at 425 at the flywheel.

slick1851

Its over rated the conversion, anyway LT4s heads can make alot of power and have more meat to port outta them.


Lt4 intake flows a little more, and can me ported out alot more....

Cam is bigger but its mild, not a bad street cam but its a baby cam...

buffman

iTrader: (9)

pretty much...

BLOCK - Should be the same LT1 casting with the four bolt mains.

CRANK - The LT4 has a special nodular iron crank with undercut and rolled fillets for added strength.

RODS - Powdered metal rods are used with a "cracked cap" instead of a machined parting line.

CAM - The LT4 cam was similar to the ones used in the high performance LT1, but it has had considerably more lift at the valve because it had 1.6 to 1 rockers.

HEADS - The heads had smaller 54cc chambers that gave the LT4 a 10.8 to 1 compression ratio. The intake ports were raised 0.100", too. The LT4 used larger intake and exhaust valves (2.00" x 1.55"). The intake stems were hollow to reduce weight and the exhaust stem was sodium-filled to improve heat transfer. The valve springs were made of oval wire to prevent coil bind with the higher valve lift and fitted with lightweight retainers to help the engine rev to its 6,300 rpm redline.

Camaro Fan

iTrader: (1)

Some people have claimed a hotcammed LT4 will reach 425 crank hp, but the particular test that hit around that number (and is the basis for that 425hp used for advertising the HOTcam + LT4 conversion kit in summit and such) was including stuff like LT headers and a custom computer EFI setup or something (ie fully custom tune).

A regular stock LT4 dynos around 300rwhp about like an LS1 from what I've read.

Edit - check the dyno page here on grandsportregisty.com, has dyno results for LT4s w/ various mods: http://www.grandsportregistry.com/dyno.htm

aboatguy

GM rated the LT4 at 330hp. As previously stated the 425 CHP number was with a hotcam and all the supporting mods.

Mike

z_speedfreak

iTrader: (3)

but dont forget the 'LT4 cam' is more aggressive than the cam found in a stock 'LT4' engine

blackedoutbird

http://www.grandsportregistry.com/lt1vslt4.htm

slowmofo

iTrader: (6)

dang beat me too it, check that site out it will tell you all you need to know

96capricemgr

iTrader: (1)

The intake DOES NOT flow more, it's ports and plenum are [pretty much the same as the LT1 BUT the ports have more material above them to allow them to seal to the taller ports in the LT4 heads and also offers something to port on to make it match the heads which it does not in stock form.

If the stock f-body engine were tested the same way it takes to get 425hp out of an LT4 HOT setup I am confident it would put out over 360 if that helps bring things into perspective.

That kit is NOWHERE near as good an option as most newbies thing so keep reading before buying anything.

94 Formula

Dyno graph of LT4 conversion kit.
w/ K&N CAI, Hooker shorties
Exhaust was dumped at catalytic
2nd run was with belt removed.