Re: 325 or 350 horse?
FYI,the later 67-68-69-396/325 & 350hp bbc's all used the same type semi hi rise cast iron intake /a q-jet/same heads/same comp ratio/dif air cleaners/dif ign timing curve/different vac adv/different fuel calibration in the q-jet like sec metering rods/same fuel pump/same spark plugs/ same smaller 7" harm ballencer/etc.
The earlier 65-66 396/325hp & 350hp/360hp motors used a different cast iron intake flanged for a square bore 600 or was it 650 cfm vac sec holley 4 brl carb & steel crank & 4bolt mains,but later 325 & 350hp 396's got nodular iron cranks & 2 bolt mains. The 396/375hp(396/425hp vette limited prod for late 65 too) used a larger 780cfm vac sec carb & AL intake for all yrs mfg'd along with a with a decent solid lifter flat tappet 143 cam & open element air cleaner assembly not to mention 11:0 comp with 4 bolt mains,steel crank,hd 7/16 rods,forged pistons,colder spark plugs/dif ign timing curve & vac adv/larger 8" harm ballencer/etc,but back to main topic here.
The main diff between the 325 & 350 hp 396's in 67-69 was some earlier motors like in 67-early-mid 68 got a steel cranks but late 68 to 69 got nodular iron cranks, the cam,an open element vs single snorkle closed air cleaner assembly,slightly different fuel calibration setup in the q-jets,slightly different ign timing curve in the dist,and a different vac adv. The 70 396/350hp was basically the same as the 67-69 396/350hp motors but it used a new flat cast iron intake from the vette but all else was basically the same other then the cowel ind fresh/cool air setup .
The 1966-69 396/325hp L35 & 1970 402/330hp LS3 cam was an extreemly mild hyd flat tappet with 198/198 deg dur @.05,.398/.398 lift,approx 113-114 LSA (?/forgot exact lsa spec)
The 1967-69 396/350hp L34 & 1970 402/350hp L34 cam called the HI LIFT hyd flat tappet was hotter then the 325hp cam but still nothing to write home about which had 214/218 deg dur @.05,.461/.480 lift,114-115 LSA (? /forgot the exact lsa spec) .
I am sure someone will chime in with anything i missed but i think i covered the main difference between the 396/325hp & 350hp & 360hp motors.
1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)
Last edited by SWHEATON; Jan 5th, 09 at 10:48 PM.