This question has been asked before. Because the search tool does not work properly I will ask it again.

I'm going to look at a 1966 big block roadster 425hp for sale.

What are the telltale signs I show be looking for to confirm 425hp car ?

The tack redline ?
suspension ?
under the hood ?
etc.

Thanks in advance,
Peter

 

If the suffix letters on the engine number pad besides the cars numerical numbers {VIN} are either "IP" for the 450hp/427 or "IK" for the 425hp/427 engines. Also a TI ignition should be present along with a 6500 red line. You get those issues covered you probably are looking at the real mccoy...

 

If the 66 was like the 67, there will also be an 80 psi oil pressure gauge.

Take some pictures of the engine pad, engine compartment, dash panel and trim tag. Post them for even better answers.

 

Lots of stuff covered in the archives but I'm brain locked myself and can't find it.

Fuel line to fuel pump has a nearly 90 deg bend in it. Small block cars are closer to 45 deg.

Accelerator lever on firewall on BB - the end sticks straight up or leans very slightly back towards firewall. SB lever leans forward over the engine.

Half shaft u-joints at the diffrential have machined caps securing them instead of straps.

Rear sway bar

There will be a transister ingition unit installed or signs that one was once there.

Copper radiator with integral expansion tank - no separate expansion tank. Expansion tank holes in fender roughly plugged with bonding agent or somethig like that.

6500 rpm redline tach. Usually an 80 lb oil gage but some 390 HP cars have had 60 lb gages. I wouldn't trust this too much.

Hood support on driver side.

Signs of past damage to underfloor area where U-joints on half shafts let go during a hard lanch. (just kidding but it's not far from truth)

 

http://forums.corvetteforum.com/c1-a...block-car.html

 

I like your '66 BB... it looks just like mine.

Back to the original poster.... Here is a list that I used just months
ago in my search for a BB (L72) 1966:

Engine Pad Suffix Code IP for the 427/450 IK for the 427/425
Big Block Hood (that's an easy one..)
Block Cast Number 3855961 or 3869942
Cylinder Head Cast Number 3873858
Posi-traction on all BB
Holley Carb 3247
No aluminum recovery bottle for coolant
Radiator is brass not aluminum
Has to have a 4 speed
2-1/2" exhaust
.375 fuel line along passenger side with 90 bend to pump
BB Throttle lover curves back to to parallel (vertical) with firewall
Transistorized ignition (you will find it behind the left headlight, open hood)
Rear sway bar 9/16" straight, with no bends
Front Sway bar is 7/8" on non F41, and 15/16" on F41 suspension
U-joints bolted with steel cap
Redline at 6500
Oil pressure gauge 80 LBS
Battery on passenger side under hood
Hood brace on driver's side

There are other engine numbers but I assume you are looking to see
if the car is a 'real' BB and not inspecting the engine.

Good luck !

 

425HP has 4 bolt mains and an external oil cool/filter tap
while the other BB cars can even have the 80lb oil gauge, and an SB car with solids has the same tach. IMO the stamp suffix and valve cover decal are obvious, but almost cosmetic.

all 66big blocks used an 11" clutch with a 14" diameter 168 tooth flywheel, EXCEPT L-88 (which used a 10.4" clutch with a 12-1/2" , 153 tooth flywheel). '444' (cast at top) clutch housing designed for use with a 14" flywheel. It was used for 1966 and very early 1967 Corvette with 427 (except L-88).
1965 block (cast) 3855962, heads 3856208
1966 block (cast) 3869942, heads (cast) 3872702, 3873858(425/450)
1967 block (cast) 3904351 after vin #173, heads 3909802, 3904391(435)

BB-SB DIFFERENCES:

80# oil (60# possible with 427/390)
5.5k redline tach 390 hp hydraulic lifters, 6.5k 425hp solid lifters
steel line from high limit oil pressure gage to engine.
front springs (tagged 3888250eb/std 3888251ef/c60 3832518ea/f41 )
front AND rear sway bar with 2 trailing arm holes drilled to mount the rear bar.
BB battery cables with riveted cable clip near RH (pass.) side of tunnel opening
BB and SB A-C cars have a LH battery holder and a washer bag
If 66-67, a brass GM radiator, plastic shroud
If 66-67, no aluminum expansion tank, mount holes filled from bottom
hood with intake port(s) and LH support after 65
all engine accessories except A-C compressor and PSpump
power steering pump hose and fitting
clutch cross shaft
lower splash shields have different exhaust cut outs
2.5 inch exhausts
exhaust heat shields
.375 fuel line pointed forward for BB pump
at, au, az, fa, fb, fc code stamped on differential
tapped differential yokes with bolt on caps
BB throttle lever curves back from pivot toward rear of car, SB is straight
TI box bolted for L79 on LH wheel well and its wiring clip under the master cylinder
If a 65, vin number higher than 13000
Registration weight shows BB added to the (327 with 3 speed) base car:
Convertible curb weight 3160
Coupe curb weight 3140
"add" weights:
a31 Power windows___ +5
co7 Hard top________+49
c48 less Heater______-20
c60 a-c____________+93
j50 power Brake_____ +12
L89 aluminum Heads__-73
m20 4speed _________-5
m35 powerglide ______+1
n40 power Steering__ +21
u69 radio __________ +21
l79 327/350 ________ -8
l36 427/390 ________+215
l68 427/400 ________+151
l71 427/435 ________+149

 

Well, I drive an hour and half to see the car. First thing I see is tach redline 5.5k (strike one) but 80lbs oil gauge. Engine casting 3969854 not sure what its for ? (Strike two) , asking 425hp money (strike three)

Thanks for all the input.

 

Time to put another CF myth to bed. Early 66 BB cars had the support on the right side as GM had leftovers from the 396 cars. The hood was then redesigned for left side supports.

 

396 or 402 '68-'72
Check for spin-on oil filter.

Any indication from the seller what lurks inside formentioned block?

 

also some of the early cars in 66 had the surge tank....

 

I believe a 5500 redline was used for the 390 HP engines so it could have started its life as a BB car based solely on the tach redline.

 

Wow, MagicV8, you just gave me an education... Thank you..

I have made up a list of items my 427/390 66 has that small blocks do not and had a 2 sided sign made up by my sign guy because I think it will be a great conversation piece when I am sitting by my car at a car show or 2 with nothing else to do...Ha!

Everytime I think I have the list complete I find other things...

Zale

 

I think he new it was non matching engine The motor runs, the car is a driver 390hp project with no hit body, muncie tranny, nice car but quoting BJ prices.

 

Well, that's true I failed to mention that.

 

What are the telltale signs I show be looking for to confirm 425hp car ?

The 425 HP has provisions for oil cooler lines ( on housing above oil filter ) there will be two plugs ... dont believe the L36 , 390 HP has provision for such , L72 425 hp ha 80 lb oil pressure gauge, 6500 red line , alum intake ( iron on L36 ).... engine code as stated by other forum members.......many more but my mind is stuck .

The Dog

 

Take off the valve covers... "High Performance" will be cast into the heads on a real 425 HP car

<<<< Like that one

 

The 80# oil gauge means nothing. Almost all of the 390 came with it also.

 

This might help, If the dash is original to the car check the date code if you can see it and see what letters are on the back of the dash cluster 425HP had the letters "LB" white tag w/red letters.

 

Yep. Unless, of course, the heads have been changed out over the last 40 or so years....