Joined: Feb 2008
A 351W will be difficult to fit between the shock towers. I'm not even sure if it would fit with manifolds, much less headers (there are swap headers for it, though). It's also a fair bit heavier, which will require stiffer springs (at least 600 lbs for a comfy ride, and 7-800 lbs for a sporty ride). They also don't get great fuel economy because of the longer stroke and larger main bearings. An Explorer V8 could be a good option, however. Keep the fuel injection, or convert it to carb and distributor. I'd second the T5, and I've had upwards of 25 mpg with one and a 262 flat tappet camshaft.
If you do go the I6 route, a 240 would be a good starting point, but for power, you'll want to get rid of the integral log intake manifold. This means either custom fab (I've wanted to put Weber side drafts on one for a while) or swapping the cylinder head for a Clifford one or an Australian head. There's also camshafts available for it, and T5 swap bellhousings. I'd also still upgrade the spindles and rear end even if you do stick with the six. I've heard of stock sixxers breaking rear axles, so an 8" would still help.
Proud owner of a '65 289 coupe. Equipped with Edelbrock Performer intake, Quick Fuel 680HR carb, ported stock heads, 282 Magnum solid cam, Hedman longtube headers, MSD ignition, and decked and ported heads. T5 transmission with hydraulic clutch. Griggs Racing GR350 suspension. 8.8 rear end. Griggs front & Wilwood rear brakes. Many more mods to come!