High Performance Big Block Cadillacs
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Author Topic: newbie - (1968 472 Swap Into 1986 Chevy 2wd.)  (Read 8712 times)
shuckles
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Posts: 7


« on: February 09, 2010, 10:31:57 PM »

Hi everyone! I am new to this and excited to be here.
I am currently swapping a 1968 472 from an Eldorado into my 1986 chevy shortbox 2wd.
So far so good. I made my own motor mounts using the truck perches and sbc mounts mated to the cad motor mounts. the cad th400 I used is a short tailshaft unit as was the old chev th400. No mods there to install it as the driveshaft was the right length already. The only issues I currently have are that the drivers side valve cover is about half an inch away from the brake booster and the drivers side exhaust manifold is only a quarter of an inch from the firewall/lower cab. Any thoughts or comments would be appreciated.
Thanx
« Last Edit: February 11, 2010, 12:50:52 PM by ~JM~ » Logged
OldSub
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« Reply #1 on: February 10, 2010, 12:10:30 AM »

Welcome!

I've not done the same swap you are so I'd have little to contribute.  What do you plan to do for the exhaust?  Will you be using stock manifolds or headers?

I'm slowly putting a 500 in a '54 GMC and I expect using stock manifolds will be tight, but I don't really want to go with headers.
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shuckles
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Posts: 7


« Reply #2 on: February 10, 2010, 07:43:44 PM »

I am going to use the stock manifolds, dual 2.5 inch with cherry bombs for now untill I can upgrade to headers. I have a friend with a set of headers that I might be able to borrow for test fitting as he hasn't installed them yet. Another issue I have encountered is my smog pump is seized. I have made up an idler pulley to replace it with but I have heard that I can use the pulleys from a 1977-1979 425 to delete the smog pump and idler pulley. if anyone knows about this please let me know.
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midnitetrucker76
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Posts: 11


« Reply #3 on: February 11, 2010, 01:32:53 AM »

Have done the same swap in a 84 2WD.  Same as you my driver side manifold is pretty close to the firewall, about 3/4 of an inch or so but I've never had any trouble with it being that close.  I've heard several times that 2.5" exhaust isn't big enough for even a stock caddy, though I never seen any test result posted anywhere.  I run 3" stainless on all mine just because a friend works a food processing plant and you wouldn't believe the amount of the stuff they throw out.  Bet i got close to 200 feet of 3 and 4 inch out back on the shelf.  Yes you can use the 425 pulleys to do away with the smog pump.  I dont remember if the timing marks are the same or not.  Or you may have to get the pointer from the 425 also.  Some of the later 500's didn't use a smog pump either.
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~JM~
Shop Keeper
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Posts: 1853


« Reply #4 on: February 11, 2010, 01:28:00 PM »

Shuckles,

 Welcome to the board. I hope you find it to be worthy of your time. There are a lot of sharp guys that visit this board from time to time & should be able to help you out. I hope that you don't mind that I added a description to the topic of your post. I'm hoping that it will draw more attention to your questions.

What type of exhaust manifolds are you using? Are they from an Eldorado or a rear wheel drive car? Is the interference that you are concerned about at the exhaust outlet, or from above where the manifold runs from the rear cylinder? You may just need to apply a bit of sledge hammer luvin' to the firewall.

I can only partially answer the question on pulleys. Unfortunately Cadillac used several different pulley & timing marker combinations. It is always a good idea to try to get the complete set of pulleys & the timing marker from whatever donor you are working with. Even so... That does not guarantee that TDC & the timing marks will align. You really need to verify that everything is correct by using one of the procedures generally used to verify TDC while degreeing in a new camshaft. Many prefer to use the pulleys from a 425 due to their stamped steel construction & much lighter weight than the pulleys from the earlier engines. For instance... My engine was removed from a '75 Eldorado. I was fortunate in that there was no air pump on my engine. However, my lower pulley is cast iron & weighs 14 lbs. or so. My engine did not have any form of harmonic dampener.(Other than a 14lb pulley. LOL) I believe the earlier engines had dampeners, but I don't know what year it changed. I don't know if the 425 had a dampener or not. I built my engine to be used in a 4x4 & figured that a 14lb pulley might actually be beneficial. (Somewhat like an extra flywheel) If I had been building an engine for acceleration. I would've used the 425 pulleys. If you are handy at fabricating small parts. You would probably be better off fabricating your own timing marker. That way you could add 35 to 40 degrees of advance to it. I'll look & see if I can't dig up a picture of the one that Terry made for me.

Good luck & please keep us posted on your progress.
~JM~
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PS. You don't have enough cam. Grin

...Summit has a kit for $99.... Shocked
~JM~
Shop Keeper
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Posts: 1853


« Reply #5 on: February 11, 2010, 02:23:24 PM »

Here's a few pics of the custom timing marker that another forum member made for me, along with the original plastic pointer & my lower pulley.


* 1.JPG (60.59 KB, 640x480 - viewed 328 times.)

* 2.JPG (59.58 KB, 640x480 - viewed 316 times.)

* 3.jpg (57.57 KB, 640x480 - viewed 315 times.)

* 4.jpg (59.93 KB, 640x480 - viewed 317 times.)
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PS. You don't have enough cam. Grin

...Summit has a kit for $99.... Shocked
Fordalac13
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Posts: 18


« Reply #6 on: February 11, 2010, 03:31:14 PM »

Ah yes the famous brand name CSOB, nice job on the timing marker Grin  Jerry
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shuckles
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Posts: 7


« Reply #7 on: February 12, 2010, 05:52:17 PM »

Thanks for the replies.
I am trying to get a set of pulleys for a 425 from the local wrecker and i will make sure to get the pointer as well. I might also build a timing pointer like the one pictured. Thanks for the pictures. As for the exhaust manifolds they are stock rwd units. The drivers side manifold is very close to the firewall where it runs out of the cylinder and might just get an attitude adjustment with a hammer! I was told that I could run 2 inch dual exhaust as the eldorado did that but it ran to single muffler! I think 2" is to small so I thought I would go to 2.5". I might go to 3" dual exhaust when I get headers but for now I just rebent my 2.5" system to fit the caddy engine.
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dave brode
C5
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Posts: 1074


Best of 11.66, 113.96, 1.59 sixty


« Reply #8 on: February 12, 2010, 09:00:35 PM »

Welcome,

The pulleys and brackets from the later 500s with no air pump will work nicely too. A belt can be run directly from the crank pulley to the ps pump. The alt belt drives the water pump.

Here's a pic of that setup [ignore the extra stuff].

Dave


* Jan08#06.JPG (94.71 KB, 640x480 - viewed 377 times.)
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3960 lb '71 C-10. 11.7-1 CR 514". PEP I beam rods floating MTS 18cc dish Probes, Elgin solid cam, home ported heads, MTS 2.19/1.84", Potter/Probe shaft rockers, edel 2115, 4781 850. Switch-pitch TH400, 12" 1800/3200 Tri-Shield convertor, 4.30 gears. Best so far of 11.66, 114.8 mph and 1.59 sixty
~JM~
Shop Keeper
C5
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Posts: 1853


« Reply #9 on: February 15, 2010, 11:48:57 AM »

  ....[ignore the extra stuff].

Dave

 Shocked Cheesy Just ignore that other stuff... It's nuthin'.... Cheesy Wink
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PS. You don't have enough cam. Grin

...Summit has a kit for $99.... Shocked
shuckles
C1
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Posts: 7


« Reply #10 on: February 15, 2010, 10:51:33 PM »

kinda hard to ignore the other stuff!!!!
i am also wondering if the rad in my truck, which is a high flow 2 core, will be sufficient for cooling the big caddy. The rad that was in the eldorado that the engine came from didn't look any bigger and looked to be a 2 core as well.
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dave brode
C5
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Posts: 1074


Best of 11.66, 113.96, 1.59 sixty


« Reply #11 on: February 18, 2010, 09:58:13 PM »

Really, guys, that was the only good pic that I had of the pulley setup. Although that setup is gone [might be on yet another air boat by now], I would like to re-turbo some day.

I suspect that the eldo got whatever radiator fit, as I bet they had at least 3 rows, some had 4.

You can probably buy something better that'll bolt in. The 2 row copper/brass will probably not be enough in traffic imo.

Dave
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3960 lb '71 C-10. 11.7-1 CR 514". PEP I beam rods floating MTS 18cc dish Probes, Elgin solid cam, home ported heads, MTS 2.19/1.84", Potter/Probe shaft rockers, edel 2115, 4781 850. Switch-pitch TH400, 12" 1800/3200 Tri-Shield convertor, 4.30 gears. Best so far of 11.66, 114.8 mph and 1.59 sixty
shuckles
C1
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Posts: 7


« Reply #12 on: February 19, 2010, 09:41:46 PM »

Thanks for the reply Dave.
When I bought the rad for my truck the company (Modine) claimed that their 2 core rad was a high flow rad and would perform as well as a stock GM 3 core rad as the cores are bigger than a conventional 2 core rad. I do have a stock GM 3 core rad that I can swap in if I have cooling issues. Or should I just swap it out anyways? I really don't want to have cooling issues so I'll do whatever is necessary.
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dave brode
C5
*****
Posts: 1074


Best of 11.66, 113.96, 1.59 sixty


« Reply #13 on: February 20, 2010, 10:31:03 AM »

Thanks for the reply Dave.
When I bought the rad for my truck the company (Modine) claimed that their 2 core rad was a high flow rad and would perform as well as a stock GM 3 core rad as the cores are bigger than a conventional 2 core rad. I do have a stock GM 3 core rad that I can swap in if I have cooling issues. Or should I just swap it out anyways? I really don't want to have cooling issues so I'll do whatever is necessary.

I would try the newer rad, and if it doesn't do, deal with it then. I have an original style 4 row copper/brass that was built using a replacmemt core and original 67-72 truck tanks [curved lower snout]. It cools well, but is thick, and I realize that some thinner cores might cool as well, due to more air moving through the core.

Fwiw, I am amazed by how well the two row, and even single row alum rads on some late model trucks cool.

Dave
Dave
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3960 lb '71 C-10. 11.7-1 CR 514". PEP I beam rods floating MTS 18cc dish Probes, Elgin solid cam, home ported heads, MTS 2.19/1.84", Potter/Probe shaft rockers, edel 2115, 4781 850. Switch-pitch TH400, 12" 1800/3200 Tri-Shield convertor, 4.30 gears. Best so far of 11.66, 114.8 mph and 1.59 sixty
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