409 External Dimensions

If I could ever get my block back from the machine shop I could answer this myself, ...but!
I'm trying to find out how long the 409 W block is from the bell housing surface to the timing cover surface. Also, the distance from same bell housing surface to the centerline of the motor mount bolt pattern. These are nice machined surfaces and should be the same regardless of engine year (I hope!).
I'm having a new chassis made for my 56' 3100 pick-up, that I'm putting the 409 in, and the fab shop wants to compare dims with the venerable small block that they have full dimensions for. If anybody has an engine out of the vehicle and can provide these I'd appreciate it. I was going to make a 3D model of the block with just the pertinent dims when the engine came back, but the shop is asking now.
 

64ss409

Well Known Member
Supporting Member 9
I measured a 409 truck block. 23 11/16" from BH surface to timing cover surface. Timing cover is off.
16" from BH surface to center motor mount bolt hole. That should be the same as sbc or bbc since they swap easily. I looked for online dimensions for sbc and bbc, but did not find those measurements.
 
Thanks Don. Is the length of the block the same with SBC & BBC or the dim from the BH to the motor mount?
I'll pass your info along to my chassis guy. I did find one place on the web that had external dim info on a whole bunch of engines. They had a row for the 348/409 but many of the dims were blank.
 

64ss409

Well Known Member
Supporting Member 9
I found online dimensions of a sbc. They are showing BH to timing gear surface as 21.78, a little shorter than a W.
 

JED

Well Known Member
Supporting Member 5
I have installed both a SBC and a 348 in my '33 Ford Roadster chassis during the mock-up stages. The engine mounts to the rear bell housing flange are the same and you can use the same engine mounts. The difference is from the engine mounts forward (and obviously the width)070218-348-350 LengthComparison-IMG_5660-c.jpg070218-348vs350Comparison-IMG_5658.JPG070218-348vs350Comparison-IMG_5668.JPG. I recorded the difference when I was mocking things up, but I would have to dig thru my build notes to get them. Here are some pictures that give you an idea.
 
I think we've got it nailed here. Thanks all for your help. The real critical dimension here is that the distance from BH to motor mounts is the same. I've got about 8" from the water pump pulley to the radiator right now with the 283 SB that's in there. So I think I'm going to have them move the motor mounts 2" forward in the new chassis. With the roughly 2" longer block length in the 409, I should still have around 4" to the radiator!
 

JED

Well Known Member
Supporting Member 5
Just an additional note - I seem to remember that the 348 water pump is shorter than the SBC pump which made a difference in the overall length between the two engines. Again, I will try to get to the shop today and find my notes.
John
 
OK but I'm only going to the water pump pulley. The radiator has a fan/shroud on it and that's what I'm measuring to. That Stovebolt 6 was a long puppy and has left plenty of length space in the engine compartment.
 

DonSSDD

Well Known Member
Supporting Member 2
The cars fan shrouds for a w were about 2 inches shorter than the sbc fan shroud which suggests the fans and water pumps were the same length give or take for both? Since the block is the 2 last inches longer?
 
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Don Jacks

Well Seasoned Member
Supporting Member 3
Most likely are,Don.The basic pulleys for the low hp W and the small block interchange don't they?
 

JED

Well Known Member
Supporting Member 5
I checked the shop this afternoon for my SBC vs 348 mock-up notes and came up empty. I re-measured the 2 engines. There is 2" difference in the distance from the front engine mount bolt to the machined surface on the block for the timing cover (the 348 is longer). I also re-measured the distance from the same surface on the front of the block to the pulley mounting flange surface on the water pump shaft on both engines. They are the same (within an 1/8"), so the pumps are the same length. My earlier comment (made from memory) was incorrect.
 

427John

Well Known Member
I think we've got it nailed here. Thanks all for your help. The real critical dimension here is that the distance from BH to motor mounts is the same. I've got about 8" from the water pump pulley to the radiator right now with the 283 SB that's in there. So I think I'm going to have them move the motor mounts 2" forward in the new chassis. With the roughly 2" longer block length in the 409, I should still have around 4" to the radiator!
Why are you moving the motor mounts and therefore the engine forward 2 inches?Are there concerns with firewall clearance?This will make an already front heavy vehicle more weight biased to the front.
 
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