Custom Sanden compressor brackets for 1965 273
My case is unusual since I have the aluminum water pump on my 1965 273. I recently switched to a 1964-65 Offenhauser 4 bbl intake manifold since didn't want to have to re-spin an aft bracket later (had 360 4bbl Edelbrock intake on there). The crank damper is original, though the 3 slot crank pulley may be aftermarket to fit the Tecumseh compressor (like York) which I recall used the outside crank pulley slot. I thought of using that bracket w/ lighter York compressor, but that bracket had cracked (re-welded it) from the heavy cast Tecumseh and my alum water pump would have required modd'ing it.
I leveraged a fwd bracket I found on a ~1989 Ram Van w/ LA engine (pre-Magnum). The first photo is the junkyard van. I don't recall taking the aft bracket since unlikely compatible since bolted to TBI intake, plus I recall it was a C-181 compressor, not Sanden, so likely varied. The aft bracket I used came with a used chrome Sanden compressor bought years ago on ebay (Chevy?). To barely clear the T-stat housing, I used a "shorty" Sanden (7SDH13) which at least cools a Honda Civic. Bouchillon requires that for their BPE4735 brackets (1969 & down SBM). Mine barely clears the T-stat hose, but good-enough. BPE shows a 2-slot crank pulley, so don't know how the inner slot in their photo compares with mine. Other Sandens (H4, H15, ...) are 1" longer than the H13 shorty. To use the BPE brackets I would need to swap back to the 1965 cast-iron water pump which would give other issues already resolved (radiator, p.s.), plus they show a Saginaw p.s. pump which seems strange since I think TRW and Federal pumps were used in 1964-69. The BPE brackets cost $252 (on sale now), though trivial compared to slant-six brackets. Anyway, I had the brackets above and like being troublesome, so made 'em work.
The RamVan fwd bracket uses the 2 w.p. holes where the alternator mounts but I didn't want to fuss with relocating my alternator. Perhaps you can make out where Mopar stuck it (last photo). Instead, I made a cross bar from steel stock (Ace Hardware ~20 mil thick), which I could barely bend on my hydraulic ram and came out too far for the R w.p. boss so had to use 2 thick washers (Ace) to get back to the boss. I show the cross-bar held up to a cast-iron w.p. which has the bosses level so no need to bend, though need to grind to clear housing bulges (or space outward). If mounting to a cast-iron w.p. and using the same pulley slots as me, you might flip the bracket around so it leans forward, which would move the compressor 0.60" forward (0.30" offset) which would overcorrect slightly for the cast w.p. being 0.60" thick (boss to timing cover) vs 1.00" thick for alum w.p. In general, V-belts work OK up to 1/8" offset and more forgiving the longer the distance, so if the pulleys look eyeball-aligned they should work.
For an aft bracket, I bent the same stock into an L and attached to left fwd intake-head bolt and front boss on Offy intake. I bent a slight curve on the press to make stiffer, then milled flat spots for boss and bolt, so don't bend that unless you have a milling machine. I used the operating flat-rod from an old garage door opener (such scrap can be golden) to weld on ears to the intake bolt and Sanden pivot ear. I tapped a 3/8-24 hole for aft slot clamp bolt. Note that the curved slots in fwd and aft brackets are on a radius to the same Sanden ears, which keeps them matched as the compressor is rotated to tension the belt. You also need the slots oriented so moving makes the belt tighter. I lucked that the V-belt clears the water pump snout, so don't need an idler pulley to clear. With its own belt, the compressor has ample belt wrap on the pulleys.
An alternate would be to share the middle crank slot with the alternator and use it for tensioning, though that reduces belt wrap on AC compressor (possible slip and squeal). Better to use 2 shared belts for compressor and alternator, but wouldn't work w/ my crank pulley since the inner pulley is smaller. I could swap in a later crank pulley (have several), though might not align without changing crank damper (thicknesses vary), and likely other issues. BPE uses a solid compressor mount and uses the p.s. pulley to tension the belt.
My case is unusual since I have the aluminum water pump on my 1965 273. I recently switched to a 1964-65 Offenhauser 4 bbl intake manifold since didn't want to have to re-spin an aft bracket later (had 360 4bbl Edelbrock intake on there). The crank damper is original, though the 3 slot crank pulley may be aftermarket to fit the Tecumseh compressor (like York) which I recall used the outside crank pulley slot. I thought of using that bracket w/ lighter York compressor, but that bracket had cracked (re-welded it) from the heavy cast Tecumseh and my alum water pump would have required modd'ing it.
I leveraged a fwd bracket I found on a ~1989 Ram Van w/ LA engine (pre-Magnum). The first photo is the junkyard van. I don't recall taking the aft bracket since unlikely compatible since bolted to TBI intake, plus I recall it was a C-181 compressor, not Sanden, so likely varied. The aft bracket I used came with a used chrome Sanden compressor bought years ago on ebay (Chevy?). To barely clear the T-stat housing, I used a "shorty" Sanden (7SDH13) which at least cools a Honda Civic. Bouchillon requires that for their BPE4735 brackets (1969 & down SBM). Mine barely clears the T-stat hose, but good-enough. BPE shows a 2-slot crank pulley, so don't know how the inner slot in their photo compares with mine. Other Sandens (H4, H15, ...) are 1" longer than the H13 shorty. To use the BPE brackets I would need to swap back to the 1965 cast-iron water pump which would give other issues already resolved (radiator, p.s.), plus they show a Saginaw p.s. pump which seems strange since I think TRW and Federal pumps were used in 1964-69. The BPE brackets cost $252 (on sale now), though trivial compared to slant-six brackets. Anyway, I had the brackets above and like being troublesome, so made 'em work.
The RamVan fwd bracket uses the 2 w.p. holes where the alternator mounts but I didn't want to fuss with relocating my alternator. Perhaps you can make out where Mopar stuck it (last photo). Instead, I made a cross bar from steel stock (Ace Hardware ~20 mil thick), which I could barely bend on my hydraulic ram and came out too far for the R w.p. boss so had to use 2 thick washers (Ace) to get back to the boss. I show the cross-bar held up to a cast-iron w.p. which has the bosses level so no need to bend, though need to grind to clear housing bulges (or space outward). If mounting to a cast-iron w.p. and using the same pulley slots as me, you might flip the bracket around so it leans forward, which would move the compressor 0.60" forward (0.30" offset) which would overcorrect slightly for the cast w.p. being 0.60" thick (boss to timing cover) vs 1.00" thick for alum w.p. In general, V-belts work OK up to 1/8" offset and more forgiving the longer the distance, so if the pulleys look eyeball-aligned they should work.
For an aft bracket, I bent the same stock into an L and attached to left fwd intake-head bolt and front boss on Offy intake. I bent a slight curve on the press to make stiffer, then milled flat spots for boss and bolt, so don't bend that unless you have a milling machine. I used the operating flat-rod from an old garage door opener (such scrap can be golden) to weld on ears to the intake bolt and Sanden pivot ear. I tapped a 3/8-24 hole for aft slot clamp bolt. Note that the curved slots in fwd and aft brackets are on a radius to the same Sanden ears, which keeps them matched as the compressor is rotated to tension the belt. You also need the slots oriented so moving makes the belt tighter. I lucked that the V-belt clears the water pump snout, so don't need an idler pulley to clear. With its own belt, the compressor has ample belt wrap on the pulleys.
An alternate would be to share the middle crank slot with the alternator and use it for tensioning, though that reduces belt wrap on AC compressor (possible slip and squeal). Better to use 2 shared belts for compressor and alternator, but wouldn't work w/ my crank pulley since the inner pulley is smaller. I could swap in a later crank pulley (have several), though might not align without changing crank damper (thicknesses vary), and likely other issues. BPE uses a solid compressor mount and uses the p.s. pulley to tension the belt.