I have a 289 in my fastback...while it seems pretty frisky, and gets me to any speed I should safely go to, I'm feeling a bit like I want a bigger engine. On the other hand, the engine runs cool, and seems pretty reliable. Am I missing out on much, not having a slightly bigger engine? I just traded 'up' to this car from a 2005 GT....
Would a 302, be a good power source, would I notice the difference? And is there a huge difference with a 351?
With all the goodies on that car, it sounds to me that 289 may have been massaged a little already. Any of those small block possibilities could give you more power if built right. That's the question . . . . how much more do you want? The 67 will even accept a big block, but you'll change the car's handling characteristics greatly. Also, working on the big blocks is "a little tight".
I would have to say (personal preference here!) that I would go with a 351w stroked. Take a little time, some TLC to a stroked motor and you will be in heaven every time that motor fires up! Nothing to extreme, I would say 408 for me, maybe a holley 750, some AFR 205 heads with nos port (better flow) edelbrock intake, a medium cam, easy 400hp probably more outta that setup. big block power without the handling sacrifice. I think one of the best commercials that I have seen in a long time sums it up fairly well..
"when you turn your car on, does it return the favor?"
As the old saying goes..."There is no REPLACEMENT for DISPLACEMENT!" That being said I would say stay 351W or smaller. They're just easier to deal with under the hood than wedging a big block (or even a 351C) in there. The 302 will give you a good bang for your buck and is probably cheaper to build than the 351W..but it comes down to preference. I certainly wouldn't turn down a 351W if I could get one for a good price. You can also get a BUNCH of power out of a 289 but you will lose a little torque.
Listen to the responses you get, do some research of your own, and look at other cars you like. Then...in the end...YOU have to decide what's best for YOU! After all, we aren't going to be driving it...you are!
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Pat Montana
1968 Coupe, 302CID, TopLoader 4-Speed,
.411 9 in. POSI...
i had the exact same problem so i took out the 289 and i stroked it to a 347 and never looked back i no for a fact my 347 can easily out sun a 351 so go with a stroker u can stroke out the 289/302 or stroke out a 351 = )
feeling small, 289 vs 302, vs 351 
