Actually I have no objection to keeping it Pontiac, but do want to make more power so if I can open this up to any other suggestions to add power. Motor is a 73 400 with 7K3 heads, needs a rear main seal as that is starting to drip and also has a leak from where the spin on oil filter is at the rear passenger side (not sure if thats stock). The motor has good compression, maintains good oil pressure, does run well (bought the car in another state, flew down, drove it 400 miles home) but just feels sluggish. I do not want to go LS1/X motor personally thus why I was looking at old school SBC. Any ideas are greatly appreciated and thank you for your input thus far