1970 C10 LS Swap, 5.3 or 6.0?

[GACST10]

Hi all,

I am sure this has been discussed a number of times before but I have not been very successful at finding a straight answer to one question.

I am considering an LS swap on my 1970 CST10. I have read quite a few posts on the process. In many cases I see that the chassis has to be modified (trimmed) due to clearance issues with the LS and aftermarket headers. In many other cases I see that some end up with plenty of clearance without the need to trim or cut the chassis.

I do not want to have to trim my chassis when I do my swap. I am inclined to choose the 6.0 to get a little more power but if this engine size is the cause of the clearance issues that I have seen with other builds, I would rather stick to the 5.3.

Can someone help me understand the cons and pros specific to the clearances of these two engines with aftermarket headers? Does buying tubular engine mount brackets make any difference?

I appreciate your help.