502 in 71 nova [Archive] - Nova Tech

: 502 in 71 nova


Randy Arnett
Nov 14th, 07, 10:01 PM
trying to find info on putting a 502 crate motor in a 71 nova haveing clearance problems with manual steering box and oil pan hitting subframe:hurray:

Big Dave
Nov 14th, 07, 10:44 PM
The oil pan is a known problem if you are still using the six quart truck pan that comes with the ZZ502 Deluxe Kit (Chevy has a service bulletin to swap out those parts for a Corvette pan and oil pump for installation by dealers for a ZZ502 into a Camaro or a Chevelle body).

Just like with a Camaro there are a number of parts that must be changed to install a BBC where a small block once resided. If you do not use all of the correct parts you will have a number of fitment problems. I am sending you a list of all of the parts, part numbers, and pictures of the required parts compared to the small block part as a separate PM.

Big Dave

70novadisease
Nov 14th, 07, 10:53 PM
Hello guys,hey Dave do u think you could send me the same info?i was also pondering doing a big block swap into one of my novas,and the info would be nice to archive!! thanks in advance!!-Dan

70novadisease
Nov 15th, 07, 10:45 AM
thanks Dave,I probably do have this magazine somewhere,much like the rest of you guys i need a seperate garage for all the hot-rod,car craft,super chevy,and chevy high performance--thanks Dave!:thumbsup:

Philip
Nov 15th, 07, 12:50 PM
welcome to the site Randy. The info Dave sent you should help a bunch with getting the BB in your Nova. The offset crossmember is available after market which is needed when you install the offset engine frame stands. The factory crossmember can also be modified to work if you are handy with metal fabrication.

Randy Arnett
Nov 26th, 07, 08:53 PM
thanks philip. Im confused about offset crossmember is this needed when installing big block in nova.I can weld and do fabrication.you mentioned a crossmember available aftermarket can you tell where so I can check on it thanks RANDY

Philip
Nov 26th, 07, 10:59 PM
The big block frame stands move the engine 1" to the right (passenger side) to give clearence for the exhaust on the drivers side. The transmission mount also needs to be moved the same 1" to the right. An aftermarket crossmember is available from most restoration parts sellers, but if you can weld it is no problem to cut off the tab and move it over. The driveshaft angle will not be a problem, u joints work better with angles then straight lines.

Philip
Nov 27th, 07, 10:10 PM
One example of the crossmember (http://www.ss396.com/mm5/merchant.mvc?Screen=PROD&Store_Code=Nova&Product_Code=FCM-85&Category_Code=)

Except for the 2 bolt mount it looks just like a 4th gen. I wouls like to get measurements of a 3rd gen to compare. If they are the same all 4th gen are offset and can be had cheap from junk yards.

gpbeau
Nov 28th, 07, 12:24 AM
Brand new member here. This topic is very timely--just picked up a '72 Nova SS with a (incorrect) 396 engine. I could use that parts list, too, if you're willing to send another copy out. Any suggestions for sourcing big block frame stands and motor mounts for this year? Same as the 1st-gen Camaro?


THANKS!

Big Dave
Nov 28th, 07, 05:56 PM
Brand new member here. This topic is very timely--just picked up a '72 Nova SS with a (incorrect) 396 engine. I could use that parts list, too, if you're willing to send another copy out. Any suggestions for sourcing big block frame stands and motor mounts for this year? Same as the 1st-gen Camaro?


THANKS!
Welcome to the board Garrett!

Sent you a PM with the info as requested. As noted the first generation Camaro is just about identical to the Nova (radiator core support and a few trim pieces differ due to different dimensions of the body, but it is basically a Camaro with a 3/4 inch longer wheel base). Place to look first for parts is with our sponsors who help fund this board. Their logos will take you to their sites for evaluation of parts availability and price.

Big Dave

Philip
Nov 28th, 07, 07:55 PM
Any suggestions for sourcing big block frame stands and motor mounts for this year? Same as the 1st-gen Camaro?


THANKS!

Yes, 67-69 Camaro mounts will fit 68-72 Nova. I beleive the crossmember will also fit.

gpbeau
Nov 29th, 07, 04:22 PM
Thanks to all for the welcomes and the great info. Dave sent the article on the swap so I know what I'm reading in the "library" tonight. One question I asked Dave--what happens to the shifter linkage when the transmission shifts 1" to the right? Is there a big-block specific linkage or is there enough slop to deal with it? Mine is a factory floor shifter for an automatic.

THANKS

youngster 72
Nov 29th, 07, 05:56 PM
My car is a 72 and it had a small block in it with a turbo 350 and i am putting in a bigblock with a th350. I looked at the article that big dave sent but I still dont know what i have to to with the motor mounts. do I have to change the frame mounts or just put solid mounts on the motor. and what is the deal with it being to the left and all that, did chevrolet not center the big block or what. also what is a flat block six cylinder???

Big Dave
Nov 29th, 07, 08:54 PM
What is the deal with it being to the left and all that, did Chevrolet not center the big block or what? Yes the motor is indeed shifted to the passenger side because a big block is Big! So big it will not fit on the centered SBC motor mounts. To make it clear the steering box (with cast iron exhaust manifolds not headers) the factory moved and raised the motor to make room. In doing so it shifted the hole in the radiator shroud, ran it into the heater box, and offset the transmission.

What is a flat block six cylinder? The original six displaced 235 cid in its final form. It is known as the stove bolt six because it used 1/4-20 fasteners to hold all of the tin on the motor just like an old coal fired cast iron stove. It differs from the newer thin-line sixes which share the bore spacing of the SBC by being chunkier with a thick cast cylinder wall you could bore over about 0.120 of an inch if desired (the new sixes will go 0.030" and have a max overbore of only 0.060").

I still dont know what I have to with the motor mounts. Do I have to change the frame mounts or just put solid mounts on the motor? This is another historical problem that confounds people but it has nothing to do with the BBC conversion.

In 1968 GM had the first ever federally mandated safety recall of a product ever. The motor mounts were breaking because the cars were getting heavier each passing year and the motors were also getting bigger and more powerful. So in 1969 all motor mounts had a new design. It is taller than the 1967 and 1968 design used on the SBC. It is also narrower to prevent you from installing the 1969 mount on a 1968 car by mistake. Every parts guy back in 1970 knew this and would get you the correct part.

Fast forward forty years and all those parts counter guys have retired. There was another major change in the motor mounting system in 1973 which GM still uses today. There is a lot of confusion as to what is the correct motor mount for a specific car. The article explains that there are in fact four different engine chassis stands and motor vibration isolation mounts. You can install a modern clam shell mount on your Nova if you desire to do so it just requires finding a donor from a Monte Carlo or a Chevelle from the mid seventies to do it.

Big Dave

Philip
Nov 29th, 07, 10:50 PM
You can install a modern clam shell mount on your Nova if you desire to do so it just requires finding a donor from a Monte Carlo or a Chevelle from the mid seventies to do it.


This will work if a small piece of steel is welded to the subframe. The 73-74 Nova subframe has the modification and other than that and the bumper mounts is identical to the 68 - 72 Nova and 67 - 69 Camaro. I can get some photos next time I go to my buddy's garage. IMO it is a much better way to mount an engine, downside is there is no provision to offset for a BB.

Randy Arnett
Dec 9th, 07, 09:58 PM
thanks philip. now i understand. just a question about crossmember mine looks like two peices of flat metal spotwelded together so the tubing style should work after relocating trans mount. has anybody used a 700r4 trans in a nova with a bigblock. dont know if any clearance problems being shifted to the right. wish i could work on the car but is cold in wisconsin this time of year Randy

Philip
Dec 9th, 07, 11:06 PM
It was cold here today as well. All the way down to 57* :rolleyes: I had to put on a long sleeve shirt to go out and work on the car.

I really couldn't live in the cold climates anymore, I must be getting old or something.

Big Dave
Dec 10th, 07, 08:21 PM
I won't tell you what I'm wearing right now it is to close to dinner time on the East coast and I do not want to ruin any ones digestion. Suffice to say it is still above 78 an hour after dark and I have not a lot of clothing on as I sit here typing in a puddle of sweat (just hung up my Christmas lights out side, most of them anyway before being driven in by mosquitoes).

In a word do not try it. I had a ZZ502 four, five years ago before I built the 582. It was in my Impala (3800 pounds before I take a seat). I went through three 700R4 in a month. I would pull them out discover what broke replace all of the broken parts with Heavy Duty parts and try again using the tried and true if you replace enough parts you will eventually make it bullet proof. Ain't going to happen. I replaced every part in the thing three times using stronger after market parts after factory Corvette and 4L60 parts failed. I replaced all of the usual suspects with billet and case hardened pieces, and still blew parts out the back of the case (which is hard on parts and cases).

It comes down to the old adage about the irresistible force attempting to move the immovable object. What gives every time is the 700R4 which is based upon the TH350 which was never put behind a BBC. Use the TH400 OD upgrade if you want an overdrive automatic. They are called 4L80e transmissions and even stock a ZZ502 won't break one. (you will need to go through it if you want more power with a bigger big block and run slicks but that is a future option).

Big Dave

Randy Arnett
Dec 20th, 07, 11:12 PM
Dave I hope that my 700r4 holds up in the nova it was in my 64 chevelle with the 502 and was prostreeted. everyone keeps talking about those monster motors in the novas what about cooling. Iwas talking to BeCool about there 750hp system hope it keeps the 502 cool.

Big Dave
Dec 21st, 07, 03:59 PM
That is a sensible way to sell a radiator. We are trying to shed BTUs and there is a direct corollary between BTUs and horsepower. Your 502 will put out an honest 540 horse at the flywheel as shipped. With aftermarket heads and a solid roller cam you can get 650 out of one. I run a BeCool in my 502 powered Suburban (I had to put that old ZZ502 someplace). My other car has a Griffin radiator. Both work great with zero cooling issues. Well that is not totally true because in the "winter", when the temp drops down to 50F, here I have no heat in the Suburban; though that could also be attributed to the 160F thermostat and fact that I still have my by-pass hose connected.

Difference between the two (besides price) is the BeCool uses a welded (fabricated from sheet stock) tank, and the Griffin uses a stamped tank which is epoxied onto the dual 1-1/2" aluminum core. When painted black the Griffin looks stock. No amount of paint can hide the slab sides of the BeCool so I leave it as is.

Big Dave

joe70
Feb 21st, 08, 10:48 PM
The big block frame stands move the engine 1" to the right (passenger side) to give clearence for the exhaust on the drivers side. The transmission mount also needs to be moved the same 1" to the right. An aftermarket crossmember is available from most restoration parts sellers, but if you can weld it is no problem to cut off the tab and move it over. The driveshaft angle will not be a problem, u joints work better with angles then straight lines.
do you have to modify the crossmember even if you have a 400 crossmember...???

Philip
Feb 21st, 08, 11:54 PM
do you have to modify the crossmember even if you have a 400 crossmember...???

Shouldn't, the 400 only came with the big block.

Randy Arnett
Feb 27th, 08, 09:44 PM
will the turbo 400 crossmember use the same factory holes in subframe

SS 396
Feb 27th, 08, 10:49 PM
will the turbo 400 crossmember use the same factory holes in subframe

Yes.

Randy Arnett
Mar 1st, 08, 10:28 PM
has anyone used a chris alston subframe with control arms and rack and pinion set up i wonder if that would solve my problem but its pricey

Big Dave
Mar 2nd, 08, 09:55 AM
Randy what problem are you having? The factory subframe will work fine with a BBC. GM made tens of thousans and hot rodders have swapped thousands more since then (In fact once upon a time Hooker made a BBC Nova/Camaro header for a BBC that was still using the standard SBC mounts).

Big Dave

Randy Arnett
Mar 2nd, 08, 05:04 PM
I guess my biggest problem is the cross member and oil pan I put a 4.5 qt on the 502 so it would fit my chevelle seems so close the big block engine stands does the taller go on the right or left

Big Dave
Mar 2nd, 08, 05:22 PM
Taller of the two goes on the drivers side; to pick it up and away from the steering gear box.

502 pans are a real problem. I tore the bottom off of mine going around a ramp from I-75 onto I-4 one morning at a higher than posted speed. Replaced mine with an 8" deep kick out stroker oil pan from Moroso that still holds seven quarts and is fully baffled with trap doors to keep oil around my Moroso pump and welded on fabricated oil pick up. It was the first step from having a ZZ502 to going with a 582. Once I had it out I changed the cam, then the heads and before I new it the ZZ502 was installed in my Suburban and I was building a Dart block based big inch BBC. (it is a disease I tell you. There is no ten step program that I know of though. I would probably modify if there were. Make it into a more efficient seven step with a bigger bore, and ... :D).

Big Dave

Randy Arnett
Mar 3rd, 08, 11:31 PM
thanks dave the directions on the frame stands was to put short one on the drivers side needless to say it didnt look right. my wife said she wants power steering as if have i didnt have clearance problems now those hooker supercomps take up a lot room

Randy Arnett
Mar 22nd, 08, 12:51 PM
Im confused about motor mounts I have energy susp mounts for v8 but the retaining bolt holes dont line up. the subframe is from a 72 nova so I looked up motor mont part numbers and they are different for a 72 v8. that part mumber for a 72 works for a big block going back to 69 camaro I ordered 72 mounts from napa they are different looking than the 71 mounts what gives here. also ordered a custom crossmember from the onlline link that philpp posted told them it was a 502 with a 700r4 they sent me the new crossmember did some measrurments and offset to drivers side 1/2 inch I called them and they said they made it with a small block in a camaro with a 700r4 bolted in made it in the car the sent it to me they said frame stands were the same from small block to big block may be I should tell them take it back and stick it any help on motor mounts would be appreciated

Philip
Mar 22nd, 08, 05:08 PM
Randy that link went to Ground Up restorations and I didn't think they did custom parts. Did they send you a different crossmember from the turbo 400 part the link went to? If so exchange it for the t400 part. If it is the same part then you may be installing it backwards, turn it around and see what the offset measures.

I think 70 was the last year for a factory BB in a Nova, look for motor mount part numbers from 68 - 70 for the correct mounts to fit the offset frame stands.

Big Dave
Mar 22nd, 08, 05:54 PM
1970 was last year they installed a BBC from the factory so you will need 1969-70 motor mounts (engine vibration isolators in GM parlance), and a set of 1969 Camaro BBC chassis stands (pedestals). Your 1972 subframe is basically the same subframe as was used as in the 1969 to '70 BBC Nova (even though the factory stopped doing it is no reason you can not). The transmission cross member will need to be a copy of the factory TH400 part (out of production), but available from restorers like Rick's

http://www.rickscamaros.com/product.asp?pf%5Fid=CM%2D3&dept%5Fid=3524

Big Dave

dconrad
Feb 11th, 09, 01:44 AM
I posted the frame graft post and am going to put BB/427 in it, would it be to much trouble to send me the list of motor mounts etc I would need for the big block install in a Nova. I know this is a nova site, and I do have a 71 ss project sitting inline after the 55