# Big Block Chevy Swap Questions



## BBM66 (Jul 24, 2018)

Hello, new here and researching info for my project. I'm sure this topic has been discussed somewhere on this forum, so I'm hoping you can link me to info pertaining to my inquiry. 
Building a 67 LeMans for the street. Full, frame off. Installing a BBC and looking at a 4L80 tranny. 9" Ford already in place. The engine/tranny combo is where my questions are. Researching to find out what motor mounts, trans mount, headers and aluminum radiator are fits for this application. Would also like to know if any modification might be needed for floor to accommodate tranny. Lastly, what else I may not be thinking of going forward, so as to avoid any unforeseen hassles. 
Thanks in advance for any links, articles or advice. Wanna have my duck in a row here. Car is almost ready for drivetrain. Thanks again!


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## bigD (Jul 21, 2016)

Don't think many here will take too kindly to putting a BBC in one of these old Pontiacs. 

But, I can only speak for myself. I think it's just downright WRONG ! No offense meant. But we're all entitled to our opinions. That's sorta what car forums are for--to give our opinions. 

As to the answer to your questions. You can probably get all the answers you need on a Chevelle site. The BBC motor mounts would the be the same on probably any same year GM A-body.


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## Goat Roper (Oct 28, 2014)

You can get a Pontiac engine big enough to destroy your frame from Butler or Sandoval, no need to Frankenstein it with a BBC.


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## BBM66 (Jul 24, 2018)

Well heck, wasnt trying to offend anyone. See, I'm reviving an old wreck of car into something fun and saving some classic metal. I happened to have a BBC thats ready to go and thought it would be fun to put it in there and save expense of building or buying another engine. I might understand your opposition here if I was doing this to a Goat, but c'mon fellas, it's a LeMans. Here, this will give you heart attack, but I bought a one owner, 63 Impala sport coupe , gutted it and turned it into an SS clone with a fire breathing 496! Why? Cuz it made it way more valuable than an old, tired 63 Chevy with a 283 and glide. I would never disrespect a GTO, SS Impala, Camaro or Superbird by bastardsizing them. I have mad Respect for any true muscle cars for sure. But those kind of projects are HUGE dollars. What I do preserves the classic hotrod while being able to afford making it something fun and special, while at the same time, making the car more valuable. I love cars, their heritage, history and muscle. If you guys choose to be purists on every little thing, go ahead, I respect that and encourage you to preserve the true American muscle cars. I'm talking about the special labeled cars...ss,rs,rt,cobra,gto..etc. For the rest of them, let people have fun for crying out loud and stop being so....old.
By the way, that 283 and glide I took out of that Impala? It was re-done, re-purposed and now lives under the hood of my 73 Vega, another fun little hotrod! Go ahead, stroke out now, I'll call 911!


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## PontiacJim (Dec 29, 2012)

Let 'em go with the big block, he probably couldn't handle the torque or power of a built Pontiac engine anyway. Chevelle big blocks couldn't keep up with the Pontiac's in the 60's, so let the disappointments begin.

1966 Chevelle SS396 (CC)
396ci/375hp, 4spd, 3.73, 0-60 - n/a. 1/4 mile - 14.98 @ 97.82mph
*1966 GTO* (CD)
389ci/360hp, 4spd, 3.55, 0-60 - n/a, 1/4 mile - 14.05 @ 105.14mph

1967 Chevelle SS396 (MT)
396ci/375hp, 4spd, 3.73, 0-60 - 6.5, 1/4 mile - 14.9 @ 96.5mph
*1967 GTO* (MT)
400ci/360hp, 4spd, 3.90, 0-60 - 4.9, 1/4 mile - 14.21 @ 102.97
*1967 GTO* (CL)
400ci/360hp, auto, 4.33, 1/4 mile - [email protected] 102.80mph
*1967 GTO *(MT)
400ci/360hp, 3spd auto, 3.90, 0-60 - 5.2, 1/4 mile - 14.09 @ 101mph

1968 Chevelle SS396 (MT)
396ci/350hp, 3spd manual, 3.31, 0-60 - 7.4, 1/4 mile - 16.0 @ 89mph
*1968 Pontiac* GTO (MT)
400ci/350hp, 3spd manual, 3.23, 0-60 - 7.3, 1/4 mile - 15.1 @ 90mph

1968 Chevelle SS396 (CL)
396ci/375hp, 4spd, 3.55, 0-60 - 6.6, 1/4 mile - 14.8 @ 99mph
*1968 Pontiac GTO *(CL)
400ci/360hp, 4spd, 3.90, 0-60 - 6.6, 1/4 mile - 14.53 @ 99.7mph
*1968 Pontiac GTO* (MT)
400ci/360hp, 4spd, 4.33, 0-60 - 6.5, 1/4 mile - 14.45 @ 98.2mph 

1969 Chevelle SS396 (HC)
396ci/375hp, 4spd, 4.10, 0-60 - n/a, 1/4 mile - 14.70 @ 101mph
*1969 GTO RA IV *(CL)
400ci/370hp, 4spd, 3.55, 0-60 - 6.1, 1/4 mile - 14.4 @ 98mph


Cubic inch for cubic inch, the Pontiac 455 HO was the beginning of the end to high HP engines and was aimed at being a low RPM torque engine rather than a true hi-performance engine. The 454 LS6 was a hi-performance engine and perhaps one of its best in the Chevelle body. The 455 HO 4-speed used the "068" cam with 288/320 duration and .406" lift. Chevy's 454 LS6 cam had 316/302 duration and .520" lift.

Pontiac's compression was 10.25 with the 454 had 11.25.
The 455HO was rated at 360HP @ 3600RPM and 500 lb/ft TQ @2700RPM while the 454 LS6 was rated a 450 [email protected] and 500 lb/ft TQ @3600RPM.

If Pontiac had upped the compression to that of the LS6 and used the RA IV package on the 455, no doubt the end result would have followed the rest - the LS6 would have gone down in flames.

And, putting a big block in a GTO brings together a bi-partisanship amid GM owners as the Chevy guys stand dumbfounded scratching their heads saying, "Why did you put a big block in a GTO?" while the Pontiac guys stand dumbfounded scratching their heads saying, "Why did you put a big block in a GTO?"

And the poor car, with a tear in its T-3 headlamp, sings that well known song by Leslie Gore, "Its my party and I'll cry if I want to cry if I want to cry if I want to, you would cry too if they big blocked you."


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## Instg8ter (Sep 28, 2010)

LOL....i think Jim hit the nail on the head HP sells cars, torque wins races. Besides all our Pontiac blocks are the exact same size, it's just a Pontiac...and thats why we love them, hell, even my wife can tell two blocks away when a pontiacs coming just by the sound.

All joking and branding aside. To help answer your question the gas lines will need to be run on opposite side, motor mounts, drive shaft, headers (that will fit), yes i believe the pan may need to be cut and modified for the trans (search on here). I'm sure there is more and others will jump in. 

Being as i only own a lowly Tempest Custom and not a true GTO, i can understand you wanting to keep a cool old car on the road and working with what parts and budget you have because thats what i did. Pontiac's can get costly to build. Fact is take anything that says GTO on it and add 25-100% of the same part for a chevy (which aside from some frame parts do not match) and its hard to find qualified builders (like Butler) familiar with the intricacy's of our much maligned motors.

Heres a pick of my smallblock 326...https://www.gtoforum.com/images/GTO...ges/GTOforum_2016/smilies/tango_face_wink.png


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## Instg8ter (Sep 28, 2010)

:wink3:


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## BearGFR (Aug 25, 2008)

BBM66 said:


> ... Installing a BBC ...


I know the hints were obscure and quite subtle, so much so that you might have missed them, but perhaps you picked up on the fact that it's not a popular approach. :grin2: 

We do love our Pontiac power and I'm no different. But to try to answer the question you asked, and to recognize that it's YOUR car and as long as you're paying the bills you can do whatever you like with it, you're a couple years too late. There was a former member here who went by the name of AlkyGTO who had a 69 GTO with a nasty 6-71 blown BBC in it that was a monster. He would have been able to have helped you navigate how to get it done, no doubt. Unfortunately, he sold the car and hasn't been seen around here in a good while. He did have some youtube videos of it out there, I haven't checked to see if they're still around..


I did find this one...
https://www.youtube.com/watch?feature=player_detailpage&v=EN1SgXune2Q


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## PontiacJim (Dec 29, 2012)

Yep, Alky's car was indeed awesome with that supercharger - even I liked that one! Like everyone else, its really your car and you can do with it as it fits your needs or budget. Just like to see Pontiac power in a Pontiac body - at least try it before swapping for something else. If you then build a Pontiac engine and don't care for it, then I am onboard because at least you gave it a shot. :thumbsup: I hope I am not around when the generation that thinks turbo'd 4 cylinders are better than sliced bread.......and all those poor old GTO's start getting the swap because its the newest rage. :nonod:


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## BBM66 (Jul 24, 2018)

Thanks for the input for sure. I love Pontiacs, particularly the early 60's GTO's and the like. They're cool and easy to do some hotrodding with and at the end of the day, that's all I am, is just a hotrodder. This particular car I'm doing now, the LeMans, was dying a slow death next to a guys barn and I just had to get it out of there. No engine or tranny, but most of the rest of it was there. It's been a fun project so far. We removed the body and had the frame sandblasted and powder coated. Thankfully, the floor just needed some minor repair and then we painted the entire undercarriage and interior floor and firewall with POR-15. A Ford 9" with 3:73's was then built and installed and the car has been in the body shop since. Itll be ready for engine and tranny by the end of Sep, thus my initial questions. This engine goin in is one I built for another project that kinda went sideways, so its available and ready to go. Nearly 700 hp with a tunnel ram and a pair of 650's. Should help the ol girl move along! Heres a few pics, fellas. Thanks


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## PontiacJim (Dec 29, 2012)

BBM66 said:


> Thanks for the input for sure. I love Pontiacs, particularly the early 60's GTO's and the like. They're cool and easy to do some hotrodding with and at the end of the day, that's all I am, is just a hotrodder. This particular car I'm doing now, the LeMans, was dying a slow death next to a guys barn and I just had to get it out of there. No engine or tranny, but most of the rest of it was there. It's been a fun project so far. We removed the body and had the frame sandblasted and powder coated. Thankfully, the floor just needed some minor repair and then we painted the entire undercarriage and interior floor and firewall with POR-15. A Ford 9" with 3:73's was then built and installed and the car has been in the body shop since. Itll be ready for engine and tranny by the end of Sep, thus my initial questions. This engine goin in is one I built for another project that kinda went sideways, so its available and ready to go. Nearly 700 hp with a tunnel ram and a pair of 650's. Should help the ol girl move along! Heres a few pics, fellas. Thanks


Hmmm. Tunnel ram, dual carbs. Velocity stacks? I might be swayed a bit, a slight bit, but a bit in any case. :lol:


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## Five Five (Jun 26, 2018)

BBM66, 

Hi, BBM and everyone, my name's Eric, and this is my first post. 

I totally get it about saving an otherwise relatively unloved car. I am doing that too. Mine had been run all the way into the ground. 

I found a '64 LeMans 2-door post in a trash storage yard. It was a completely gutted half-shell, with zero attached parts except for a windshield that was bashed-in. That means no frame, nothing forward of the firewall (pure air), no interior, no mechanicals whatsoever, not even the frame. It was about as low-down as a car can get, and the owner was going to have it crushed. All of the parts that made it a car such as the entire chassis and engine and front body had already been scrapped years before. What it DID have was a clear title. 

I took it home and am building the car 100%. I fully intend to, as we used to say, make the scene in a world of ricers and millennials who know nothing of our Nation's recent heritage. 

I received PHS documentation and found that the original buyer had ordered the car with every heavy-duty part available and no comfort options, save tinted glass. I was told by the seller that the original owner had ordered the car through a Los Angeles dealership and upon delivery had the 326 immediately replaced by the dealership with a 421. As this car was manufactured before the GTO was available, the LeMans with its big motor, 4-speed, and heavy duty chassis was something pretty special when new. 

It sits on a '66 El Camino frame (all 14 body mounts line up) that I spent 9 months modifying for strength. There are 4 additional frame rails, 3 cross-members, webbing, plating, gusseting, it's both widened and narrowed, etc. The entire front of the factory frame forward of the engine cross-member is gone after I cut it away and re-designed it (along with the core support I located) to carry a more modern cross-flow radiator. 
The new suspension, brakes, steering are all state-of-the-art. The engine is an EFI (Holley full sequential HP) blueprinted 572" tall-deck Rat with all top shelf parts. The axle is a Dana 60, with a face-plated TKO-600 and big U-joints in between that and the rear. The body went to bare metal and I found that it was a solid shell with only some trunk floor and lower quarter issues. It is a full ground-up build with all new parts and fasteners. What I'm after is an early 70's street/strip style car like we used to run at Lions and OCIR. The only difference would be that the parts are all modern and the engine produces around 830 HP. It will be my daily driver, regardless of the fuel mileage. I can afford the gas, but went with the (very) expensive full-sequential EFI in an attempt to get at least some shot at, say, 10 mpg street and 14-15 freeway. (OK, guys, shhh... I can hear you laughing...) 

I spent a year building an instrument carrier in the same general shape as the factory style, but in metals instead of plastic. The interior is 100% new. I found excellent condition tinted glass and polished it with Eastwood stuff and the glass is spectacular, save for the windshield which is new. I installed fresh power windows, but hedged on the Vintage Air since the space it would occupy under the dash is full of computers. 

It is flat impossible to locate the original frame or VIN/date stamped parts or the installed SD421. It ain't never gonna be able to go back to the way it was when it was built... _on 11C of '63..._ very poetic, eh? 

I think Ponchos are excellent cars, and have always liked the basic Pontiac engine design philosophy. In the mid-seventies I got to know the guys at HO and ran a fast 400 in my '69 Firebird. I'd love now to have an intact GTO from just about any year '64-'72, but this '64 is what I found and I just didn't want to see a car that was built in the same week Kennedy was assassinated in Dallas just go to its death along with so much else of our nation's cultural heritage that seems to be getting trashed lately. 


HOWEVER, in my defense: I ask that the Court of Pontiac Faithful take judicial notice that there is a Ram-Air IV sitting in my garage for an eventual build and use in the '64. So please don't hate me too much...

This is going to be a major-league roadworthy car, run easy 10s at the drags, and in beautiful black-on-black it will attract more attention than the Porsches and BMWs my colleagues drive (and which I fully intend to park next to). They're already envious- it's really obvious- they all have what are commonly available status symbols, and I'll be showing up in a hand-built American Legend. My '64 will be the star of the parking lot full of $100K + cars simply because of what it is- a top shelf pre-GTO big-inch American muscle car from the era of the Saturn V... and from one of the most exciting times to be alive in the most powerful nation in the history of the world. 

Let's hear it for a strong America !

Thanks for letting me talk

Eric


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