307 engine, who is keeping ? and why

[hotsy]

I recently purchased a 70 c10 lwb with 51,000 org miles,has a 307 with a 3 speed on tree,runs excellent and with low miles iam tempted to leave it in and run it till it dies, has anyone else ever kept their org 307 engine opposed to putting a stronger engine ? I do have a 350 4 bolt with 45,000 miles on a stand and runs good but at the same time I hate to pull a good engine out ...anyone got any input , if you left your 307 in yours lets hear your story.