[BruceWilkie]

Info you may want to know. As always double check dimensions. I've copied down what I used and dont think I transposed anything but measure twice cut once they say.

Figured Id post all this info as a separate thread . From my posts on the blockplate thread... http://forums.maxperformanceinc.com/forums/showthread.php?t=717531

Yesterday, 11:23 PM
BruceWilkie
Ultimate Warrior
Join Date: Nov 2003
Location: Murfreesboro TN
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Quote:
Originally Posted by BruceWilkie
55-60 for sure used 7/16" bolts not sure 61-64. The ring gear is a different diameter on the 64-earlier blocks (at least with bell mounted starter). The adapter drawing in the book positions the starter relative to that ring gear. I dont have that spec handy. Modern ring gear is 13.98" the early one is 14??? (I think 14-5/8").

I think I have the dimension from crank center to starter shaft center(radius) for use with modern ring gear written on one of my drawings. I'll check on it later.

BTW ...dowel holes... dont enlarge them they center the bell. If Bell is off center you use offset dowels to correct the difference. Early blocks thru 60 the dowel measures .498" nominal not 1/2". The newer blocks the dowel hole is .6216/.6226 NOT 5/8"(.625")

15/32"(.46875") holes for transmission bolts will accomodate 3/8" or 7/16" bolts. That is the hole spec on the adapter drawing. Most modern blocks use 3/8 bolts.

I'll follow up with more data.

I did write down the dimension for locating the starter centerline when using a bell mount starter and modern 13.98" ring gear.... From crank centerline to starter center the radius is @ 7.3725". The vertical distance(not radius) to the starter centerline from the dowel horizontal centerline(modern bell) is still 4.565"/4.575"

On the plate itself make the starter pilot hole 3-3/8" to 3.5". Make your pilot plate 3.25" for a tight fit around the starter pilot. Dont drill the bolt holes yet(in either piece).

With plate bolted to block,flywheel/flexplate installed, and solenoid removed from starter...clamp the starter to the plate snug but loose enough to allow hammer tap to move it. actuate pinion into flywheel and check pinion to ring gear mesh. Should be .020"-.030" between outer edge of ring gear tooth and "valley" between pinion teeth. (average paper clip is right around.025" if you need a tool...but mic it 1st).

Once you have that set, tack weld the starter pilot plate to block plate. Recheck gap before final welding.
Then install the solenoid and position starter as you want it and mark the bolt holes.

Not shown in the adapter drawing... Dowel horizontal center to pan rail(crank horizontal center. I checked a few virgin blocks and the dowel center to pan rail measured from 2.328" to 2.330".

The T400 drawing may mislead you on the vertical centerlines off the lower outboard holes and the dowel vertical centerlines.
Crank centerline to dowel centerline is 7.690"
Crank centerline to lower hole centerline is 7.800"
Lower hole centerline to dowel centerline is 1.880"
Middle bolts center to crank centerline is 6.300"
Middle bolts from dowel horizontal centerline to bolt center is 2.500"
Upper bolts centers from crank centerline is 3.540"
Upper bolt centers from dowel horizontal centerline is 6.26"

The starter pilot plate is 7/16" on the 61-64 block adapter.

The 55-60 block the starter pilot plate is thinner because the bell face is recessed more (relative to the crank flange) than 61 up blocks. I used 5/16" plate but you could try 3/8" plate if your starter over engages.(or use a 1/16 shim with the 5/16 plate)
Dowel holes... 0.498" or .6221" ...drill smaller and ream to size... they need to be a very snug fit.

OK... here are the 55-60 pattern dimensions. These can be overlaid on the t400 to 61-64 adapter dimensions to fit a modern trans and 61-64 starter and modern flywheel to to early pattern blocks.

Observe comments above on starter mounting and pilot thickness.

First off Pan rail to dowel centerline was 2.806 on my block (another block with machined rail was 2.774). (good reason not to weld starter pilot till all is fit to block)
Note the early dowels are higher than 61 up blocks and smaller at .498". Early blocks use 7/16" bolts.
Quarter inch plate puts modern bell in same plane as modern block with no crank/flywheel spacer needed. It will require welding nuts on plate(or riv-nuts if aluminum plate) where modern trans bolts will go... except upper two which are very close early to late. (hole enlargement in bell to accomodate 7/16 bolts.)
Also suggest Flat head counter sunk allen head bolts(7/16) to mount plate to early block for clearance reasons.

The dowel vertical center to crank vertical centerline is 6.861"
The lower bolts center to dowel center is 2.32"
The lower bolt center to crank centerline is 6.98"
The middle bolt hole centers are 2.329" from dowel horizontal centerline.
Middle bolt centers are 7.242" from crank vertical centerline.
Upper bolt centers are 5.779" from dowel horizontal centerline.
Upper bolt centers are 3.5525" from crank vertical centerline

BTW IMI has a mini starter for 61-64. A 55-60 starter can work if you change the bolt pattern to straight across. RobbMc has a mini for Buick nail head that has infinite clocking and pilot is same 3.25" the bolt pattern looks like 61-64 Pontiac. RobbMc also has a mini with 3.25 pilot and straight across pattern for Eldorado and Toronado and could be fit as well.

Thanks to Jack Gifford and Taff2 for their dimension info below.
Attached Thumbnails
Attached Files55-60 Dimensions.txt (902 Bytes

[gavin]

Thanks for the info as I am doing an adapter now for a 287 to turbo 350.By the way my 63 336 uses 7/16" bolts. A very helpfull post.