Big Block 'fit' questions?? - Team Camaro Tech
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post #1 of 9 (permalink) Old Nov 10th, 05, 06:00 AM Thread Starter
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Big Block 'fit' questions??

I am putting a BBC 402 with Hooker Headers in a 68 that used to be a 6-cyl car. We sat in it last night just for a 'trial' fit to see how we will have to modify the headers. The motor mounts will have to be changed or modified to move the motor off the firewall to clear the throttle linkage and allow room for the transmission fill tube. After this, I figure I better go ahead and get my power steering pump and a smaller brake booster and anything else I can think of that may cause a 'fit' problem.

My question is to those of you who have been there....
- what water pump? long or short??
- What radiator and electric fan combo? ( i want to keep as cool as possible for cruising. No racing.)
- What power steering parts?
- What size brake booster?
- What else am I missing that might pose a fit problem???

Thanks for all your help!
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post #2 of 9 (permalink) Old Nov 10th, 05, 06:29 AM
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Thumbs up Re: Big Block 'fit' questions??

I would first see what fits like stock before getting anything?? (Booster????)

Then use all stock or NOS stock parts and you will be fine unless you want a period correct car.

I didn't change my heater outlet to the BB one so my heater hoses are rightat my pass. side valve cover but is fine to me.

And I am running a Summit House brand aluminum generic rad. to cool my big motor instead of a stock one for some weight reduction and it is BIGGER.

BB frame and rubber or poly engine mounts and just use a poly three hole tranny mount and install the bolt in the middle hole through the pass. side crossmember hole. Short water pump and all needed stock pulleys will be fine!


PS., and fwiw, a BB decked out with an aluminum water pump, al. intake, al. E-brock, Performer AFB type carb., al. heads, al. rad., headers, battery in the trunk and a f/g hood isn't ALL that much heavier than an ALL iron, stock SB, imho..

The heads alone remove something like 50 pounds !!!!

pdq67 is offline  
post #3 of 9 (permalink) Old Nov 10th, 05, 06:38 AM
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Re: Big Block 'fit' questions??

Doing the same thing to my 69, so I can help some.

There are big block specific frame mounts (the two bolt on "towers" in the cradle under the engine) for the fist gens. Offsets the engine to the passenger side about an inch to resolve clearance issues on the driver side. Pulls the engine forward a little too, I think (it's early). If you need more clearance at the firewall, you can always slide the entire subframe forward. You should probably check that the subframe is aligned within Fisher Body specs anyway. Do a search on here for subframe alignment to find a thread that has the Fisher Body diagram for 68. If you can't find it, I can scan it and post it or email it to you.

Water pump depends on what accessory brackets and pulleys you want to use. If you are buying new 68 BB brackets and pulleys, you'll want a short pump because that's what 68 had and is what you'll need to get things lined up. If you are using the 402 brackets and pulleys, it'll be a long pump. I don't think there is any clearance isssues with either pump in a 68.

The rad/fan issue will have to be answered by someone else. My 402 is so mild, I'm going to try a stock replacement rad and thermo clutch fan to start.

On the power steering parts, what do you need? Are you using an existing box, and just need a pump? Lots of us have installed a 3rd gen steering box to get rid of the "pinky" light steering of the 1st gen box, but I'm not sure what you're asking for. I'm just running 69 BB brackets and a 69 replacement pump.

Unless you plan to use some really tall valve covers, a stock size (11") booster fits fine when the BB stands and mounts are used. Mine has plenty of clearance.

You'll need a BB trans crossmember, and that may be a little bit of a pain depending on the trans you run. The BB crossmembers had the same offset (1" or so) as the engine mounts to keep the engine/trans straight in the car. BB manual cars used one cross (looks just like the small block cross except the cutout for the mount bolt holes is shaped different and the holes are off set) that you can use for a manual or TH350. BB auto cars (TH400) used a tubular cross.

Wait, you're worried about room for a fill tube, so you're running an auto. Which one?

Have you dealt with the heater core yet? BB uses a different core than the 6/small block cars; heater hoses on a BB come out of the center of the box cover.

Almost forgot the coil springs. Big block springs are taller to compensate for the extra weight. You may have clearance and handling issues, but some folks just run the 6/SB springs.

69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!
Eric Kammerer is offline  
post #4 of 9 (permalink) Old Nov 10th, 05, 11:22 AM Thread Starter
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Re: Big Block 'fit' questions??

Thanks for all the info!! Sorry I didn't include more info about what I had.

Here is what I am gonna be running...

I have a 402 bored .30 over, Edelbrock Perfermor RPM Air Gap intake, .520 cam, closed chamber heads...everything balanced...short valve covers and Hooker Competition headers. For Trans, I have a Turbo 350.

My brother was going to possibly modify the existing frame mounts to save me some $$$. Is that possible or should I jsut get the BB ones you mentioned? And you are right, ain't no telling if the car is lined up correctly. Who knows.... :>

Since I have had experience with a motor runnign 'warm', I want to do whatever it takes to keep as cool as possible. I definately will run a electric fan as well. Those clutch fans get loud and take away horsepower from my experience in the past. I just want to hear it and feel it run!! :>

I have no power steering and am will need to get pump and all for that.

I also have a set of alum. pulleys on my 'to-buy' list.

I have a big brake booster that came with my brake kit since my car had NO power disk brakes. I will be using 'short' valve covers but figured the brake booter might be VERY close and that the smaller booster may look better and ensure ample amount of room. If you think it has plenty, I may jsut keep what i have.

On the crossmember issue, are you saying that I am ok with the crossmember I have since I am running a TH350?

I have not dealt witht he heater core yet. I will add that to my list as well. I am plannign on getting the A/C kit (Vintage AIr, i think). Have you messed with that at all?

I am getting new big block springs. The guy i bought the car from had a 305 in it with big block springs that he cut 1 ring off of. If there is trouble with the BB springs, I may just try out what I have since they are BB springs (minus 1 ring) and swap later if I need to.

Again..thanks so much for your help. If you think of more, just let me know!

68 Coupe, BB 402, TH350...
Future color - ??
bigblockgirl is offline  
post #5 of 9 (permalink) Old Nov 10th, 05, 11:47 AM
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Re: Big Block 'fit' questions??

Michelle -

You can modify small block frame stands, but the right ones are available repro and only $65/pair. I have a feeling if you use small block mounts you'd have to use a manual steering box (not enough room for the driver side header with power box). It's really tight, even with the offset.

To use a 6 or SB trans crossmember, you'll have to do like Paul said and use a tranny mount that has three holes and just put one bolt in the center of the mount, through the hole in toward the passenger side of the crossmember. Or watch for a BB crossmember for sale, usually less than $100 or ebay.

I don't know about the Vintage Air kit (I drive verts, and get all the air I need that way), but if you do a search on the forum, I know quite a few guys have that setup.

If the springs in the car now are BB with a coil off, they may be perfect. Most of us here complain about how high the new replacement springs make our cars sit. I have Moog 638 BB springs in mine, and went ahead and cut a coil off to get it down "normal". Doesn't look like it will cause any ground clearance issues, but I'm not running headers.

I'm on dialup now, so posting pictures is out of the question. I'll post a couple to show booster clearance and the like tomorrow if you want. Front sheetmetal is off the car for another week or so, so I can shoot whatever you need to see.

69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!
Eric Kammerer is offline  
post #6 of 9 (permalink) Old Nov 10th, 05, 12:37 PM Thread Starter
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Re: Big Block 'fit' questions??

Where did you fin dhte $65 pair of frame mounts?
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post #7 of 9 (permalink) Old Nov 10th, 05, 01:21 PM Thread Starter
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Re: Big Block 'fit' questions??

I found them!! Rick's First Gen...

Thanks again! I will try to get a page set up of my 'progress' pictures.

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post #8 of 9 (permalink) Old Nov 10th, 05, 01:27 PM
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Re: Big Block 'fit' questions??

right here:

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post #9 of 9 (permalink) Old Nov 10th, 05, 04:43 PM
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Red face Re: Big Block 'fit' questions??

I'm sorry, Michelle!!

I should have said everything stock '68 BB..

My BAD b/c a 396 BB came stock in the '67/ '68/'69 cars so stock is fine.

Please re-read what I said about the tranny crossmember and you will be fine back there! My 496" car is that way now and I'm still using my stock Muncie 4-speed shifter!


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