187 heads are swirl port heads found on 305 TBI motors. For certain applications they are a great head. What is your intent with these heads? They can support almost 300 hp in stock form. They need little timing and are fast burn heads. They make great power (compaied to TPI heads) below 4200 rpm and improve dramatically with port work. If you have visions of an all out drag car that will run above 5000 rpm making 400+ hp than these heads are not for you. If you want a reliable (can run 87 ocatane and only necessitate around 28° of total timing), great low end, fast burn head for a 300hp application than they may be what you want. For motors larger than 305 CI one may opt for the 193 (350 SP heads) which have been proven (by Fast355) to support 320hp and 400+ lb ft.
Refer to these threads for further review.
TBI and TPI headflow data (TBI and TPI heads: headflow data) We like these heads now? (WTF? we like these heads now?)
Note Dewey316's dyno results of a direct back to back comparison of ported 416 heads and stock 187 heads. Had the 187's been ported the power difference above 4500 rpm would have been less.
