If it is a 2.100 rod journal you will have issues.

 

With 50 or 55s?

 

wouldnt waste my money unless its a raised cam block

 

i had alot of issues with both set ups 50mm and 55mm stick with the standered bearings

 

regardless of the BEARING DIAMETER or base circle diameter.. you will have clearance issues with the lobe itself if it is anything of larger relative duration... with a common 2.100 journal rod..
not worth the trouble with a standard cam height block.....

it is often accomplished with a special narrow / clearanced 1.88 basic rod bearing rod assy....in a standard cam height block...

 

There is absolutely no advantage to useing a larger cam bearing diameter and have to use a small base circle lobe....!!!!

 

I have used the Dart SHP PRO blocks which has a BBC journal and with the Callies 2.100 Compstar rods 3.750 stroke and with a std. B/C have always seen around .060 cam to rod clearance.

A 50MM roller is about .021 bigger so its going to be a little bigger and the Callies Ultra HD rods would the rods of choice or going to a smaller journal rod would be another choice.

Going to 55MM roller cam bearings you should go to a Raised cam block it can be done but on Big bore block you will cut a lot of the bottom of the cylinders inward side.

On a side note I have some 55MM babbit cam bearings coming out next month with a groove and one oil hole for a 2.282 housing bore, Babbit cam bearings seem more popular now over roller cam bearings. More drag using roller cam bearings and more harmonics as well which travel thought out the valve train.

It really depends which rods you are using!!

 

I will be boring the block myself so price is not a factor.

Looking at running a callies magnum 3.75 stroke with honda journals and probably the callies pro i beam rods with the 3/8 bolts

Ive heard mixed thoughts on roller cam bearings but so far theyve seemed to help. At least on the spintron.

 

Talked to the guys at Grumpy Jenkins shop a few years ago and I was told more power in using babbit bearings.

 

do as you please,

but I agreewith cnc carl about going to roller cam bearings..

lots of tout and wisdom.. as we BOTH are of the few that actually can bore out the cam tunnell housing ..
My advice is to stay with a babbitt insert bearing as cnc suggests...

time has told the results of many long term users of roller bearings...
they aint all that it is cracked up to be....
a spin tron result is not the only thing that matters..

and by the way, the housing bore diameter that the block has to be bored to, to fit in the roller type inserts is not the same as a common babbitt insert..
... wall is different thickness so the housing bore is different..
even when the cam journal is the same.

 

Im pretty aware of housing bore sizes for 50mm, 55mm, 60mm roller bearings, vs 55mm, 60mm ect ect babbit. I can machine blocks just fine. My question was will i have to watch out for clearance issues with 50mm roller bearings in std cam height sbc block with a 3.75. Thanks.

 

I like roller bearings, I run tons of them. You can run the same set for years. No harmonics problems on my stuff.

Not much of an advantage as far as going to a bigger base circle in your case though. I would probably just go 2.283 and use a 50 mm. Then if you chose you could do as Carl suggested if you ever wanted to and use 55mm babbit bearings.

 

the issue is not with the larger diameter of each of the possible bearing diameters......
.... it is the fact that the larger diameter bearing, whether a "contained roller" or a "babbitt type" is that this is done for the basic first reason to get the base circle and relief diameter of the core LARGER TOO..
and when the larger diameter lobe base circle is employed... the flank of the lobe will STILL HIT the common rod / crank stroke setups..
as carl has stated.. he knows of one such setup that will in fact clear..
but there is no advantage of using a larger bearing or roller bearing if you have to use a "small base ciecle camshaft" becaue the TWISTING and torsional and llobe flank wear is not "better" with a small base circKle in comparison to a common standard lobe base circle....


and as carl and I have stated many times previously to others that pose the similar questions about converting a block to a larger insert or roller bearing..
. SOME certain BLOCKs will have issues with the oil passages..
...some blocks should NOT have the same larger diameter installed in the rear most location...( some have reaL bad oil flow galley in rear most location or casting is real real thin...!!!)...
... and some blocks should just NEVER be attempted to be converted EVER....

 

and some are better to use a 429/460 ford insert on/in the front four locations and the STOCK original insert in the rearmost location next to the distributor gear....