And So It Begins- The Big Block Swap

TINY · Guru

RE: And So It Begins- The Big Block Swap

seventy2plus2 · Canadian Poncho Superstar!

'69 Wiring harness is likely simpler than a '70 harness, as I don't think TCS wasn't used in '69 yet. Also using a Turbo 350 simplifies things.

Harness changes you need to make are related to the additional heat of a big block, but are mainly cosmetic:
1) wire from coil to starter changes to a wire with white braided coating - I got some at a shop that repairs lamps, etc.  (keep in mind the braided wire from firewall to coil is resistive).
2) purple wire from firewall to starter has white braided wire for about the last foot - I got some at a shop that services kitchen appliances.
3) I see on the 427 the oil pressure sender is towards the front of the engine. I've never seen that before. It should be above the oil filter, angled 45 degrees up using brass fittings.   (do youself a favor, don't put the sending unit on until the motor is in the car) You'll need to extend the blue wire that goes to your existing sender.

Re motor mounts, believe it or not I used ones purchased from Canadian Tire. As the front end continued to drop each time I added more stuff (like coolant) I needed to change the front coil springs, I've got he box at home and can get you the part number. I used Moog if I recall.

As you're using a turbo 350, your existing crossmember and frame mounted brackets should be ok. One thing to watch for with your diff is to ensure the pinion yoke and your rear u-joint work together. As I put in a driveshaft from an original 454/turbo 400 car, I needed to put in a wider yoke for the larger u-joint. Luckily I was able to take one off a spare diff I had.

gparis7 · Canadian Poncho Superstar!

My last big block swap was a 454/M21 Muncie into a 307/PG 68 Impala. Fortunately I did not have to change the trans mount or driveshaft yoke for the M21, as the T400 swap would have required. I changed the motor mounts, fabricated a rad spacer and did some heat shielding on the wires around the starter & manifolds. And that was about it. I ran stock manifolds, through 2.5 inch pipes that came on the donor car. The front springs & radiator were OK for the 454 as the Impala was an A/C car.

Canadian Poncho · A Poncho Legend!

Thanks for the info. Seventy, I could use the part numbers for those engine mounts. As for ignition, I'll continue to run HEI which Ken converted the car to when he had it. My goal is to have everything I need before I pull the motor out of my car. I don't want to have a lot of down time.

59poncho · Poncho Master!

i have a double core rad that i put in the trans am and only ran it for maybe one summer i think. If it would fit its yours for a t-shirt and a can of matte black tremclad spraypaint!

Canadian Poncho · A Poncho Legend!

Thanks for the offer Trevor but I don't think that rad will fit.

59poncho · Poncho Master!

no proplem Todd.I was going to put it in the 59 but i would have to move alot of stuff to fit it right. Im not that adventerous yet to try that.

seventy2plus2 · Canadian Poncho Superstar!

I no longer have the boxes for the engine mounts (which is odd as I don't throw anything out), but the receipt was sitting where the boxes should be. Cdn Tire part # 17-5995-4 description 2283 motor mount were $17.59 each in June 2004. If you're talking about the mounts that bolt to the frame, if I recall in 69 they're different for small blocks and big blocks. For 70, they were the same, I have a set of those in the garage. Part # for the front coil springs is Moog 6322.

-- Edited by seventy2plus2 at 21:53, 2009-01-05

65beau · Addicted!

as for your number 1 cyl looking white and having rust on your smog is right in line with having moisture, could possibly be coming in from seapage ever so slight from the water pump or head gasket through the head into port 1. I bet once you pull the heads youll see penetration rust line on the mating surface. Moisture is the only thing that can make your inards rust and is in line with making inner combustion parts go white. So does when the mixture is too rich, however richness doesnt make rust. Just my opinion now

Canadian Poncho · A Poncho Legend!

I was hoping I wouldn't have to pull the heads as the engine was a good runner but maybe I should just to be safe?

427carl · A Poncho Legend!

69Laurentian wrote:

I was hoping I wouldn't have to pull the heads as the engine was a good runner but maybe I should just to be safe?

If you do that, you won't stop

.. Someone will say,you should check bearings, and someone will say, you should check the bores, and someone will suggest, getting it balanced, and someone will say change the pistons, and some will say, get a bigger cam, and then a bigger carb.. The original beauty, of this was to bolt it in, and have big block w/o big dollars in it..If you keep going, you might as well buy a crate motor!

p.s. a new timimg chain would be good, and bolt it in, and drive it.. Its a big block with "torque"

TINY · Guru

I agree bolt it in and go for it. You can buy the 454 out of the vette and rebuild it next winter. but for now just drive it.

65beau · Addicted!

I agree, just slam it in your car and bag the hell out of it....right. Still, no one had any suggestions to his orig question, just bag on it.

2drpost · Uber Guru

69Laurentian wrote:

Decisions decisions.. We'll see how the funds go and that will pretty much decide whether I cam it or not.
seventy2plus2:Yes, I'm swapping the 350 in my 69. How many changes did you have to make to the harness? So far I only see minor changes (eg: oil pressure sending until wire)

I'm going to run the THM350 for the time being.

CDNPONT: I have a 12 bolt posi lined up, again it's a matter of getting some $$ together. Likely will pick it up in the Spring

Carl- I'd like to run headers.

Lots of little things to consider as well. I'll need mounts, oil pan (427carl has one) , a bigger rad, front exhaust pipes, springs, and I still need to replace the front ball joints. I also would like to improve the handling of the car at some point too.

todd,
wiring is pretty well ok, just extend the oil guage wire to the hole just above the oil filter.
if you use headers, you can cut and use those new pipes with them.
your original mounts will work. if you buy new insulators, be sure you get the correct ones, there are 2 different mounts used(width difference).
rad should be ok if it's in good condition.
springs will be ok, b/blk is about a 100 lbs more.

Canadian Poncho · A Poncho Legend!

That's good news. I ordered new Delco upper and lower ball joints as well as control arm bushings from Carl Stevenson's dealership (yes, ordering them from him was still cheaper with shipping than from the GM store I worked at located 2 minutes from here-any wonder why I left? furious

). I figure I better get the front end up to snuff before the big block swap.

Todd

67BBSD · Canadian Poncho Superstar!

Todd, I agree with the rest, drop it in-that way you work out all the install bugs-you know the engine runs at least as good as the old small block-once its in and working you can always pull it to do cam/tranny etc... it might be fine just the way it is-close your eyes put it in !

4SPEED427 · A Poncho Legend!

69Laurentian wrote:

That's good news. I ordered new Delco upper and lower ball joints as well as control arm bushings from Carl Stevenson's dealership (yes, ordering them from him was still cheaper with shipping than from the GM store I worked at located 2 minutes from here-any wonder why I left? ). I figure I better get the front end up to snuff before the big block swap.

Todd

You might have received a slight "adjustment" on the purchase price as a fringe benefit since you are responsible for starting this site

Canadian Poncho · A Poncho Legend!

It'd at least be cheaper doing it this way!

67BBSD wrote:

Todd, I agree with the rest, drop it in-that way you work out all the install bugs-you know the engine runs at least as good as the old small block-once its in and working you can always pull it to do cam/tranny etc... it might be fine just the way it is-close your eyes put it in !

67BBSD · Canadian Poncho Superstar!

69Laurentian wrote:

It'd at least be cheaper doing it this way!

67BBSD wrote:

Todd, I agree with the rest, drop it in-that way you work out all the install bugs-you know the engine runs at least as good as the old small block-once its in and working you can always pull it to do cam/tranny etc... it might be fine just the way it is-close your eyes put it in !

theres no doubt after you get it all in your going to want to make changes anyway-so the first time get it in make it fit and change everthing the next time. as for the 350 turbo I had a friend that raced a built 468 cube 69 Camaro for years-it had a 350 turbo in it, I don't believe the Twelve bolt is the first thing you need either depending on driving habits.

hey how about a bench seat 4-speed ?

-- Edited by 67BBSD at 22:35, 2009-01-11

4SPEED427 · A Poncho Legend!

I put 10,000 miles on my Acadian with the 427/TH350 combo. It will be fine Todd. Same goes for the 12 bolt. Good advice about getting the engine swap to begin with and work from there.

Canadian Poncho · A Poncho Legend!

The gearing is a little lame in the current diff. I'd like to wake it up with something like 3.23's or 3.55's

67BBSD · Canadian Poncho Superstar!

69Laurentian wrote:

The gearing is a little lame in the current diff. I'd like to wake it up with something like 3.23's or 3.55's

my deepwater blue 67 SD396 325 hp with 400 turbo had base 273 gears-15.20 91 mph

4SPEED427 · A Poncho Legend!

69Laurentian wrote:

The gearing is a little lame in the current diff. I'd like to wake it up with something like 3.23's or 3.55's

There is a 3.36 ratio available for your 10 bolt. That would be a nice in between gear. It's a bit tough to find, but I know some years of Nova wagon had that as the base ratio.

Canadian Poncho · A Poncho Legend!

I heard somewhere that the 10 bolt in my Laurentian was one of the weakest ones made. True?

Canadian Poncho · A Poncho Legend!

BTW, there is a 3.36 12 bolt posi available to me.