G Man

this motor was in my 78 Pantera 24 when I bought it about 10 years ago advertised as 475 H.P and ran every bit of that. . The boat was set up full race with bolsters etc. The motor blew me away when I test drove the boat in Florida. When I got it back to Pennsylvania I converted the boat to pleasure to use for a while and then sell. Which I did. I decided the 475 H.P. motor was a "keeper" and I have had it ever since. Got out of boating for a few years as our family grew and now have a 25 Outlaw with a 500 H.P. motor.

Guess It's time to sell the motor as I have not done anything with it for all these years.

Block is stamped 7.4 Hi Perf, nothing on front engine pad. 4 bolt mains, number 14015445 stamped on block.

Heads are stamped GM Hi Perf, and are large square port, with gold roller rockers, open chamber, stamped 14096188. I believe these are the biggest heads GM has made.

Motor is all together and has been in my heated garage. I spin it over by hand each month and Everything from the heads to the underside look brand new.

What do you guys think it is worth?

Outdrive1

Chevy Big Block Cylinder Head Codes (ALL)

Casting No Years CID Intake Exhaust Chamber CC
330864 1970-81 366/427/454 2.06 1.72 Open
330865 1970-84 366/427/454 2.06 1.72 Open
336765 1973-84 427/454 2.06 1.72 Open
336781 1973-85 454 2.06 1.72 Open 113
343771 1968-85 366/427/454 2.06 1.72 Open
343772 1976-84 366/427/454 2.06 1.72 Open
343783 1975-78 454 2.06 1.72 Open
346236 1975-87 454 2.06 1.72 Open 113
346238 1975-87 454 2.06 1.72 Open 113
353049 1970-73 402/454 2.06 1.72 Open 113
473328 1968-85 366 2.06 1.72 Open
3856206 1965-66 396 2.06 1.72 Closed 97.2
3856213 1966-70 366 2.06 1.72 Closed
3872702 1966 396 2.06 1.72 Closed 98.4
3872702 1966 427 2.06 1.72 Closed 98.4
3876875 1966-70 427 2.06 1.72 Closed
3904390 1966-67 396 2.06 1.72 Closed 98.4
3904390 1966-68 427 2.06 1.72 Closed 98.4
3904393 1966-68 366 2.06 1.72 Closed
3909802 1966-67 396 2.06 1.72 Closed 100.9
3909802 1966-68 427 2.06 1.72 Closed 100.9
3917215 1967-69 396 2.06 1.72 Closed 100.9
3917215 1967-70 427 2.06 1.72 Closed 100.9
3917219 1966-70 366/427 2.06 1.72 Closed
3931063 1969-70 396 2.06 1.72 Closed 100.9
3931063 1969-71 427 2.06 1.72 Closed 100.9
3933148 1969 366/396 2.06 1.72 Open 112.1
3933149 1969-70 427 2.06 1.72 Open 122.1
3964280 1966-70 427 2.06 1.72 Closed
3964280 1966-71 454 2.06 1.72 Closed
3964290 1969-70 396/402 2.06 1.72 Closed 100.9
3964290 1969-71 427 2.06 1.72 Closed 100.9
3964290 1969-72 454 2.06 1.72 Closed 100.9
3965198 1969 396 2.06 1.72 Closed
3975950 1968-70 366/427 2.06 1.72 Closed
3986133 1970-85 366/427 2.06 1.72 Closed
3986136 1970-84 366/427 2.06 1.72 Closed
3993820 1971 402 2.06 1.72 Open 113
3993820 1971 454 2.06 1.72 Open 113
3999241 1972 402 2.06 1.72 Open 113
3999241 1972 454 2.06 1.72 Open 113
6272292 1971 402 2.06 1.72 Open
6272292 1971 454 2.06 1.72 Open
10101136 1991-94 454 2.06 1.72 Open
10121033 1978-88 454 2.06 1.72 Open
12352783 1979-93 454 2.06 1.72 Open
14025175 1983-93 454 2.06 1.72 Open
14081044 1986-90 454 2.06 1.72 Open
14092359 1986-89 427 2.06 1.72 Open
14092360 1985-89 454 2.06 1.72 Open
14101398 1986-90 454 2.06 1.72 Open
3856208 1965 396 2.19 1.72 Closed 108.9
3873858 1966-67 396 2.19 1.88 Closed 108.9
3873858 1966-68 427 2.19 1.72 Closed 108.9
3904391 1965-67 396 2.19 1.88 Closed 106.8
3904391 1965-68 427 2.19 1.72 Closed 106.8
3904392 1967 427 2.19 1.72 Closed 106.8
3919840 1967-69 396 2.19 1.72 Closed 106.8
3919840 1967-70 427 2.19 1.88 Closed 106.8
3919842 1968-69 396 2.19 1.88 Closed 106.8
3919842 1968-70 427 2.19 1.84 Closed 106.8
3946074 1969-71 396/402 2.19 1.88 Open 118
3946074 1969-72 454 2.19 1.88 Open 118
3964291 1969-70 396/402 2.19 1.88 Closed 109
3964291 1969-71 427 2.19 1.88 Closed 109
3964291 1969-72 454 2.19 1.88 Closed 108
3964292 1970 454 2.19 1.88 Closed 109
3994025 1971 454 2.19 1.88 Open 118
3994026 1971 454 2.19 1.88 Closed 118
6258723 1971 454 2.19 1.88 Open
6272990 1971-94 454 2.19 1.88 Open 118
10051128 1990-94 454 2.19 1.88 Semi Open
14011077 1989-94 454 2.19 1.88 Open 118
14044861 1989-94 454 2.19 1.88 Open 105
14096188 1987-94 454 2.19 1.88 Open 118
14097088 1989-94 502 2.19 1.88 Open 118
3830817 1965 409 2.06 1.72 Closed
3852583 1963-65 409 2.19 1.72 Closed

Outdrive1

Chevy Big Block Engine Block Codes (ALL)

Casting Years CID Main Comment
340220 1972-76 427 tall truck
345014 1974-86 454 truck
346236 1974-76 454 2 Chevelle, Monte Carlo
359070 1974-90 454 truck
361959 1973-85 454 car & truck
364776 1968-84 427 tall truck
364779 1968-88 366 tall truck
473478 1968-84 427 tall truck
1401544 1975-87 454 truck
3782870 1968-76 427 tall truck
3855061 1966-67 396
3855961 1966-67 396 2 passenger, chevelle
3855962 1965-66 396 4 passenger, Chevelle, Z16, Corvette
3855977 1965-67 366 tall truck
3866961 1966-69 396 Chevy, Chevy truck
3869942 1966-67 427 2/4 corvette, passenger
3873858 1966 396 4
3902406 1967 396 2/4 Camaro, Chevelle
3902466 1965-67 396
3904351 1967 427 2/4 385, 390, 400, 425, 430, 435, corvette
3904354 1966-67 366 tall truck
3916319 1968-85 366 tall truck
3916321 1968 427 2/4 385, 390, 400, 425, 430, 435, corvette
3916323 1968 396 2/4 camaro, chevy II, chevelle
3918319 1966-70 366 Chevy truck, GMC, tall truck
3925521 1968-85 366 tall truck
3928319 1969-73 366 GMC, tall truck
3935439 1968-69 427 2/4 335, 390, 400, 425, 430, 435, Corvette
3935440 1968-69 396 2/4 Chevelle, Camaro, Nova
3937724 1968-85 366 tall truck
3937726 1968-84 427 tall truck
3946052 1969 427 4 ZL-1, aluminum, Camaro, Corvette
3955270 1969 427 2/4 335, 390, 400, 425, 430, 435 Corvette, passenger
3955272 1969 396/402 2/4 Camaro, Chevelle, Chevy II, passenger
3955274 1968-85 366 tall truck
3955276 1968-84 427 tall truck
3963512 1969-71 427 2/4 335, 390, 400, 425 COPO, 430, 435, Camaro, Corvette
3963512 1969-72 454 2/4 345, 360, 365, 390, 425, 450, Chevelle, Corvette, Monte Carlo
3963513 1973-76 454
3965440 1968-69 396
3965449 1968-72 396
3965540 1968 396
3969854 1969-72 396/402 2/4 240, 265, 300, 325, 330, 350, 375, Camaro, Chevelle, Chevy II
3969854 1969-73 454 2/4
3969858 1968-84 427 tall truck
3999289 1972-78 454 2 Chevelle, Corvette, Monte Carlo, truck
3999290 1972 402 2 Chevelle, Camaro
3999293 1968-85 366 tall truck
3999294 1968-84 427 tall truck
6272176 1968-76 366 Chevy, GMC, tall truck
6272177 1972 402
6272181 1973-76 427 tall truck
3755011 1959-61 348 2 250, 280, 305, 320, 335
3771705 1959-61 348 2 250, 280, 305, 320, 340, 350, 2-bolt
3788068 1962-63? 409 2 340, 380, 400, 409, 425, 2-bolt
3795623 1961 409 2 360, 2-bolt Impala SS
3798962 1961 348 2 250, 280, 305, 340, 350, 2-bolt
3830814 1963-64 409/427 2 340, 400, 425, 427ci-430hp, 2-bolt
3844422 1963?-64 409 2 340, 400, 425, 2-bolt
3857656 1965 409 2 340, 400, 2-bolt
353049 1973 454 corvette

Outdrive1

I'd be willing to bet it's not an LS6, sorry..........

G Man

Thanks, someone told me it was an over the counter LS6??? And not one that came in a 70 - 71 Chevele or Corvette. Does that make since??

satisfactionII

Original LS6 .. probably 6-8K maybe a little bit more. someone building a numbers matching SS Chevelle would give plenty. Rare.

G Man

I agree.But what is this motor?????

fastfunco

someone must know more about this motor - because I have 2 of them - the gold roller rockers is whats super unique as my motors have crane roller rockers too- and - I too thought I had original LS6 engines - only mine are unfired as new - grandfather had them all these years in California-
Here is what my motors have in them -
4 bolt mains casting number 14015445
Crankshafts are cross drilled and nitrided and p/n is 3967418
the rods have 26 on them they are the Dimple 7/16 forged steel rods
Cam- performance street and marine p/n 14096209
crane roller rockers 13-170
Chrome molly pushrods
Heads are 118 cc open chamber square port 6272990 with 325 cc intake runners
Pistons are 3999295 GM 9 to 1 compression with these heads
Mini starters
100 amp alternators with awesome brackets
brass water pumps again with super trick easy to service mounting brackets
chevy performance distributors - points style to clear blowers
and Magnafuel 500 fuel pump filter assemblies - I called Magnafuel and they sell for 800plus and the guy said mine were old- but nothing had changed- had me open up the filter and the stainless steel screen to ld us they were never used -

he also had 2 outdrives and velvet drives - outdrives are king cobra with all the updated red cables and tags that say 21 hours on them - they look brand new - 2 hydrolic cavitation set ups sea strainers that look expensive -

my research showed that these motors were built for the corvette production in 1971- they are exactly what was in the 1970 corvettes but they swapped to open chamber heads and brought the compression down to 9 to 1 under pressure from some government agency -- - however chevy had to reduce the advertised HP even more due to EPA issues and these engines were not used - they were sold as crate engines from 1971 on thru the 80s - further digging showed that my harmonic balancer - PN 3963532 IS 1970 1971 LS6 high performance and the flywheel p/n 3973457N is also corvette high performance 70/71

Since finding this thread I am now stumped- these engines have more history we are missing - I believe they are the LS6 motors that chevy decided not to use and are authentic- all the part numbers match up to that regard- one of you posted his block number was for a truck-- I have a list of p/ns from chevy that shows that casting number was used from -- im going off memory here so correct if im wrong - 1971 thru 19976 all used that number and 1 other as you will notice - no more numbers stating with 3 after 1971 and only 1 or 2 numbers starting with 140---

some marine connected outfit obviously added the pushrods and crane rockers somewhere down the line as what are the chances 3 motors with the same components all original LS6 except for the pushrods and rocker arms -?? a billion to 1

my grandfather had these engines for 20 plus years in Cali- I have kept them thinking they would be worth a lot of money one day as mine are as new the day they rolled out of chevy - no rust - perfect condition - my grandfather released the valve spring tension when he got them , or I should say he backed off all the rocker arm nuts - which by the way are the modern crane style nuts with the set screw down the middle -

I don't know how this came about - but both of my motors have 8-71 Blower Drive Service superchargers on them with pullies - belt and idler- along with BDS fuel rail and stainless braided lines feeding 2 C&J engineering holley 780 double pumpers with the trickest billet linkage system ive ever seen - all billet aluminum and stainless heims joints - simply hook in throttle cable and that's it - mine also had BDS timing tapes on the balancers- but get this - the tapes would have never worked - they were way off - where the real 30 degrees advanced should be - the tapes said 60 degrees- very very strange -
I did find out thru C&J that BDS in 1991 did build some finished engines and we believe these 2 were from that time - BDS has been sold and has no record of anything back that far now--

so- how much are 2 unmolested original LS6 motors with 9 to 1 compression and 8-71 blowers worth complete turn key

and who put the crane roller rockers on these motors????

SB

iTrader: (1)

The Merc 370hp motors had Crane Gold Roller rockers.

The LS6 motors (neither the Chevelle one's nor the over the counter lower compression ones) as I remember them did not have Roller Rockers. Cam off the top of my head where solid lifter with 242* at .050" and just over .500" lift. I have had my hand in all 3 (merc 370's and the 2 different LS6's), but way back in early to mid 90's so my memory will be close but not 100%.

fastfunco

I did find in my grandfathers garage next to the motors 2 air intakes - stainless boat air filters that say mercruiser 420 on them - did merc make a 454 in 1990 or 1991 with 420 hp - because it would not surprise me a bit if these motors were mercruiser - they probably bought a ton of these LS6 motors since Chevy had thousands of them ready for 1971 production vettes - they switched to a different motor of less HP late in the game prior to the 1971 production-this would make sense!!!