Maybe a big block car originally??
 

Hi all,

As mentioned in my prior post, I recently purchased a 66 roadster. The car has a non-original 327, which I'm restoring to include 'mostly' original components. Along the way, I've noticed some oddities that make me wonder if this was originally a big block car. I searched the forum for all of the tell-tale signs of the big block, but wanted to get some expert opinions. This is more about "corvette enthusiast' curiosity rather than some desire for a big block car.

OK, this is what I have found so far....I took this list from a prior forum post...

Big Block Hood (that's an easy one..) Nope, this has a small block hood. But it's been painted in the past. Not sure how to date the hood.
Block Cast Number 3855961 or 3869942 Not applicable, it now has a 327
Cylinder Head Cast Number 3873858 Not applicable, it now has a 327
Posi-traction on all BB Yes, but rear Diff appears to be a replacement anyway
Holley Carb 3247 New Holley replacement on 327 4160 w/ electric choke now.
No aluminum recovery bottle for coolant No recovery tank present on car, no holes in Pass Fender apron.
Radiator is brass not aluminum Has a big block brass radiator in the car
Has to have a 4 speed Yes, 4-speed, also has large BB bellhousing and 168 flywheel
2-1/2" exhaust Exhaust is 2 1/2 in rear, but smaller (2") in front to match up to NON-327 Ram Horns
.375 fuel line along passenger side with 90 bend to pump Fuel line measure 3/8" OD. Seems to have a 90 at the fuel pump (see pic)
BB Throttle lover curves back to to parallel (vertical) with firewall Seems to have the BB bends (see pic)
Transistorized ignition (you will find it behind the left headlight, open hood) Haven't found this one yet...may be gone.
Rear sway bar 9/16" straight, with no bends No rear sway bar.....Diff and rear springs are not original.
Front Sway bar is 7/8" on non F41, and 15/16" on F41 suspension Front sway bar is 7/8" and seems original
U-joints bolted with steel cap Caps on outer bearings. Inner bearings (Diff side) are u-bolts. But it appears Diff was replaced
Redline at 6500. Redline is 5500, consistent with 390HP
Oil pressure gauge 80 LBS Yes, 80psi gauge. My cluster label is 'LD' (see pic). I can't really see the date code while cluster is in the car.
Battery on passenger side under hood Yes, battery on Pass Side
Hood brace on driver's side No, brace is on RH, but mounting bolts are on both sides, so could have been swapped with hood.

I can't seem to find much info on the 'LD cluster', but some prior forum posts indicate this could align with the 427 390hp engine.

I'm sure all of these parts could have been replaced over the past 50 yrs, but what are your thoughts about these findings? And....are there other things I should look for that might help identify the original engine combo?

Thanks for your time and input.

EDIT: Car production date is approximately June 17, 1966 based on VIN



https://cimg6.ibsrv.net/gimg/www.cor...d9058ca39.jpeg
LD Instrument Cluster
https://cimg7.ibsrv.net/gimg/www.cor...42e0b531e.jpeg
Instrament Cluster
https://cimg0.ibsrv.net/gimg/www.cor...02e10bf77.jpeg
Fuel line 3/8"
https://cimg2.ibsrv.net/gimg/www.cor...80acd3132.jpeg
Front Pass Spring
https://cimg4.ibsrv.net/gimg/www.cor...973634f03.jpeg
Front Sway Bar
https://cimg6.ibsrv.net/gimg/www.cor...d06964ac9.jpeg
Big Block Radiator
https://cimg8.ibsrv.net/gimg/www.cor...e6bc1474d.jpeg
Accelerator Pedal

Both SB and BB fuel lines were 3/8. But the bend at the fuel pump differs between the two. To help your cause it does have a BB bend.

Thanks again for the quick reply Nowhere. Any wisdom on the LD cluster? Can't seem to find much content related to this letter designation.

It looks to be a 300 tach with a 80 lb oil pressure so something was changed

Don't we all assume that the most labor intensive thing to fake a BB car is the fuel line? That 90 degree bend at the fuel pump adds to the case.

Ray

if the car was never restored or body removed from the frame. A quick look at all the body mount bolts and mounts will tell us that

A lot of 390 hp cars received 80 lb oil gages. You don’t even have to change differentials to switch from BB yokes to SB yokes or the reverse. Just pull the differential, pop off the c-clips and install what ever half shaft yoke you want. It does seem to have several BB clues and it’s unlikely anyone purposely would fake BB car details like the radiator, fuel line, sway bar, and accelerator arm while sticking a SB motor and hood on it. The TI system was not mandatory for 427/390 cars like it was for.L72 cars so the absence of TI amp mounting holes up front doesn’t mean a lot.

Thanks everyone. I have to agree with DansYellow. The car was painted and probably had body work, but I do not think anyone did a body off on this car. I read that the 427/390HP cars had 5500 tachs. I will try to get a date off this cluster (in time). I also can't imagine anyone wanting to install a big block radiator and mount with this 327 engine.

I'll check the Diff when I have the rear lifted higher. In the meantime, I took a picture of the body mount bolt (under door towards front). I check the metal....some surface rust, but no holes or rot. Frame is very solid and birdcage seems solid (with surface rust).

Thanks again for all of your input. :)



https://cimg0.ibsrv.net/gimg/www.cor...bf3c8aba0.jpeg

the bolt doesn't look like hasn't been touched in decades....

but I would clean out the cowl drain hole

And here's a fun fact. I owned a 66 Big Block 427/390 HP (NOM) coupe and sold the car to a nice guy down in Maryland about 10+ years ago....which is why my name on this forum is RJP66BigBlock. Now, I own a 'small block' 66 that 'may' very well be an original Big Block car. What a crazy world.....

Ralph PM sent

Nowhere man......I plan to do a lot of cleaning haha. Thanks again for your help.

Ralph - looks like you've gone through a pretty extensive list of things to check. Got one more for you...the Radiator Core Support. I just walked out to my garage and compared my 66 L79 core support with my 66 L72 core support and they are different.
The Bigblock support has those top bracket 'through-holes' further out to the edges. Can you take a few pics of yours, front and back of the ends up top?
Mike T - Prescott AZ

Vet65te.....do you mean these holes??

https://cimg3.ibsrv.net/gimg/www.cor...b523ce7fb.jpeg

The holes I'm referring to are up on the top-most bar. I just took a couple pics, one of the 66 L79 Coupe's core support and the second one is the 66 L72 Roadsters core support.
Mike T - Prescott AZ
https://cimg7.ibsrv.net/gimg/www.cor...79fd97aa30.jpg
https://cimg9.ibsrv.net/gimg/www.cor...e692903847.jpg

I will try to take some additional photos later today.

Ralph - I've been checking and measuring both my 66's, to see what the differences are and turns out those holes/slots I mentioned on that top bar exist on both core supports, both SB and BB.
But...after looking through a lot of old archived threads, I think I now have a more definitive way to determine if that core support in your 66 is for a Bigblock or a Smallblock.
To check this, you'll need to get under the front of the car so you can look up at the core support.
The smallbocks used twin tubular pins that dropped into rubber bushings and the lower part of a Smallblock core support has two cradles with round depressions to accommodate those two rubber bushings.
The first pic was taken underneath my 66 L72 roadster and it shows the lower brackets that support the Bigblock radiator are u-shaped just like the upper brackets and they accommodate rubber pads that secure the Bigblock radiator at the tanks.
The second pic I'm attaching is of my 65 396 roadsters core support...since the engine/radiator aren't in yet. The 65 Bigblock radiator was 2" wider than the 65 smallblock but still used the twin pins/round rubber bushings to secure the bottom of the radiator.
Mike T - Prescott AZ
https://cimg8.ibsrv.net/gimg/www.cor...aaccb35c3e.jpg
https://cimg9.ibsrv.net/gimg/www.cor...94910051f8.jpg

Mike, your radiator is a little prettier than mine - but I think my mounts looks similar to your big block. I also spoke with a fellow Corvette Forum contributor and big block owner (thanks Mark!) over the phone this evening and found a few more clues. I have two J-hooks on the passenger side firewall, consistent with big blocks. The top J-hook is a little squished, you you can see both. I included a picture below. I'm feeling more confident that this is indeed a big block car.....probably a 427/390 hp (based on the cluster gauges). I guess I need to start hunting down a '942 engine ;).

https://cimg4.ibsrv.net/gimg/www.cor...3e41de941.jpeg
https://cimg4.ibsrv.net/gimg/www.cor...fbc412392.jpeg

Hey Ralph - that's great news. Not a ton of evidence but enough and after all these years, lotsa stuff got changed so it's looking like your 66 started out as a factory L36.
My 66 L72 has a production date just about 10 days later than yours, 6-28-66. Mine lost it's original 427 a long time ago and in its place now is a good running 396.
Nice torque but the 396-325 horse cam is a bit weak so I started looking around and found a June 66 #942 4-bolt block, steel crankshaft (#6223)
and a pair of '67 L-88 Aluminum Heads. Got a few other projects ahead of it so it's going to be a while before I get to it.
Truth is, if you come across a 396/402/454 in good shape, if you were considering it, you could dress it up to look like the original L36 427 and with the right components,
make it perform like the original too.
Mike T - Prescott AZ