I have a 83 Mecham Racing Trans Am with stock 305. I want to keep this car original since they're were only 150 made this year. But I would like to know the difference between these motors? I plan on doing work to the engine but I would like to know the difference, does anyone know?
Well I appreciate it.

 

If you mean an L69 305 then the diff between that and an LG4 is:

9.5:1 compression
aluminum intake
bigger exhaust
bigger cam
also required a 5 speed w/ 3.73 posi

I've never heard of a Mecham before except for the GTPs that they soup up now.

 

Yeah, and the L-69s also had a carb with slightly different secondary calibration and a more aggressive timing curve in the computer chip.

 

I have an L69 but I have 2.43s and 700r4... Unless that was the options in 83 in which case I'll be quiet

 

I believe that the LG4's mostly came with aluminum intakes also... a few came iron, depends what year you have I think.

The other difference is the HO has 40 more Hp and makes it's torque @ 3200 instead of 2800 RPM

 

The V8 options in 83 were:

Lg4 4 speed auto or 5 speed stick... 3.08(only auto), 3.23 and 3.73 rears

LU5 (cross fire) 4 speed auto, 2.93 and 3.23 rears

L69 5 Speed stick, 3.73 rear

 

Ok Thanks for the help!

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83 Mecham Racing Trans Am
Restoration in Progress..

 

HO also had different exhaust manifolds(I think) and definitely an electric fan.
Craig

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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com

 

I have a 84 l69 and mine was, i ripped out the 305 and installed a 350 but mine is a 305 HO 5 speed i removed the rear cover and 3:27 was stamped on the gears but i checked the id code under the interior center console and it said i had a 3:73??? I still am not sure what gearing i have.there is a website that states all the stats for each engine.
http://www.f-body.org/tech/tech.htm#cam3rd

 

You've never heard of a Macho T/A??

 

I can attest to that It freaked my out that my firebird had an aluminum intake and my z28 did not
SSC


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85 Camaro Z28, Cowl induction hood, Black-355/TB400,3:42 posi, Tons of goodies but if you ask, "Its stock"
82 Firebird, White, red in six months-355/TB350,3:42 Powertrax posi. Not an insane amount of goodies but it runs like a motha!
76 Chevy C10, Firemist blue, 355/Muncie HD 3speed,3:73 TorqLine posi. Show me another 12sec@4800ft SBC street truck??
91 GMC 1500 Sierra 4x4, Red, Was 4.3 now the proud recipient of the Firebirds LG4. 305/5 speed.
56 Buick Special, OG Blue&White, V8/auto. Maybee one day I'll get it going.