Who here uses a big block oil pump on their small block? I just realized the guy that built my motor last time did. I'm not sure why or what you would benifit from it? More volume? Anyway, I'm angry now because I finally got everything to put my motor back together and now I can't do any more tonight because Napa is closed and I ordered a small block pump. I guess the 5 bolts on the pump cover instead of the usual 4 should have given me a hint. Oh well at least I learned something. I also believe the shaft is shorter that hooks to the distributor when I compare it to a regular SMC one. Maybe because my block has been decked? I don't know. Anyone else have any input as to why this may be? Now I have nothing to do except sip on this fine Rum and Coke.
The Big block pump bolts onto the small block but requires a short, (5.625" long) shaft (not the same as the even shorter front sump shaft). Moroso makes one #2290 . If you are using a 400 block, you'll need to machine the pump shaft opening to 9/16".
The big block pump eats a lot of power and, IMO, isn't really necessary. Some people believe the extra teeth on the BBC pump reduce spark scatter, but I haven't seen any documentation that there is any benefit.
AL, do you know if the pickup tube is 5/8" or 3/4"? The one I took off is 3/4" and I want to know if it will fit that M99HVS pump. My pickup has been modified for my 10.5" deep pan so I want to reuse it. Thanks.
I'm sure this has been asked a thousand times. Does anyone have a ballpark idea how much more it does take to spin a high volume pump? Is it the high pressure or high volume that takes the extra power to spin?
The last time i had a bigger pump like that it was a DZ 302 pump that my uncle had laying around and we used it in my first 350 engine. He said chevrolet used them in Z28's for better hi rpm oiling.
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