B or RB in A body

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dart_68

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I was wondering if any would know if there is a significant difference between an RB or B motor fitting into an A body? I have "heard" that B motors fit a little easier because of the shorter deck height.

Thanks.
 
I have a 440 in my 70 Dart. Pretty tight, but doable. Tri Y Headers fit good. Spark plugs are easy to change from below. Thinking about building a 383 stroker for it, 438, as I have all the parts, including the pistons. Will up the C Ratio from 7 to 1, to about 11 to 1. Also, the B is about 40 lbs lighter.
 
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With factory air I have to use stock style valve covers to clear the blower motor with the RB block and a dropped air cleaner helped. If money allows I'd stroke a B block
 
what year is your A body? earlier cars (up to 66 or 67?) had a narrower distance between the frame rails. i've put a 440 in a 65 dart and headers were a nightmare to make, even the fenderwells that i did. the 383 i'm putting in my 68 valiant now is much roomier, wider engine bay and smaller motor. with the schumacker headers i still have factory power steering and will keep the a/c although with a modern sanden compressor :thumbsup:
stroker kits can get me to as much as 496 cu in so that along with the fact that a 383 is cheap compared to a 440 and it's smaller made it a no brainer for me.
neil.
 
From what I've seen either works but the RB exhaust choices seem a little better. They Schumacher tri-y headers and the TTI headers both fit a little better on an RB than on a B. They fit and work with either, but you have a little more room around the suspension, starter and transmission with an RB. Of course, with the RB you have less clearance for the hood, heater and master cylinder. There are more intake manifold choices for the RB and main bearings are easier to find. I'd say it is a bit of a coin flip.
 
Thanks for all the responses. I'm looking at building a 512" stroker. 440's are pretty cheap but the 400 block is considered stronger (some of them). It would be going into a '73 Duster.
 
what year is your A body? earlier cars (up to 66 or 67?) had a narrower distance between the frame rails. i've put a 440 in a 65 dart and headers were a nightmare to make, even the fenderwells that i did. the 383 i'm putting in my 68 valiant now is much roomier, wider engine bay and smaller motor. with the schumacker headers i still have factory power steering and will keep the a/c although with a modern sanden compressor :thumbsup:
stroker kits can get me to as much as 496 cu in so that along with the fact that a 383 is cheap compared to a 440 and it's smaller made it a no brainer for me.
neil.

just don't try a 383 RB..
 
If you don't want to spend almost a thousand dollars on headers, use the B engine. Then you can use the Hedman big block B body headers. They fit with only a few dents.........and some people have had them fit with no mods at all. Depends on how your engine sits in the car.
 
If you don't want to spend almost a thousand dollars on headers, use the B engine. Then you can use the Hedman big block B body headers. They fit with only a few dents.........and some people have had them fit with no mods at all. Depends on how your engine sits in the car.
Hey Rusty, are you referring to the 78030 Hedman header at Summit? They are the same shape as the Summit brand, which are only $183. Only difference is in the flange thickness at 1/4", Hedmans are 5/16". Also wondering if you think the Hooker Super Competition headers would fit, as I have a set of those. THANKS
 
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I was after power steering and the Schumacher kit fit the bill
 
Hey Rusty, are you referring to the 78030 Hedman header at Summit? They are the same shape as the Summit brand, which are only $183. Only difference is in the flange thickness at 1/4", Hedmans are 5/16". Also wondering if you think the Hooker Super Competition headers would fit, as I have a set of those. THANKS
Reviews (Summit) were not so good on those...I've wondered what headers would be best fit for my '68 383 Barracuda w/power steering..have not heard of any yet anyway..
 
I have the Schumacher Tri Y headers on my 70 Dart now, 440. The fit is good with power steering. Going to build a stroker 383 for it in the spring. (438), so may try a set of another type and see if they fit. I have 2 sets laying around. I'll check fitment when I have the motor out. Do regular headers increase power levels over the tri Y headers?
 
Here's a picture of some clearanced hedmans.

IMG_2046.JPG
 
Hey Rusty, are you referring to the 78030 Hedman header at Summit? They are the same shape as the Summit brand, which are only $183. Only difference is in the flange thickness at 1/4", Hedmans are 5/16". Also wondering if you think the Hooker Super Competition headers would fit, as I have a set of those. THANKS

Not sure about the hookers, but the Hedmans have been documented in many builds. You can even see a build with them on bigblockdart.com And yes, I believe that is the right number. I have never seen anyone say the Summit headers fit.
 
Here's a picture of some clearanced hedmans.

View attachment 1715288479

Yeah that's them! I promise you, those dents look much worse in the picture than they really are. It doesn't take much. Also, if someone was good with a mig welder, they could remake the tubes in the right places. They are really close as they are.
 
Do the tri-y's work with power steering? I heard that ill have to cut down the steering column sleeve fpr an RB swap.
 
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