Motor swap problems

[89Sierra409]

Hello everyone. I have an '89 Sierra k1500 reg cab long box. I put in a 409 sbc (400 small block +.040, Vortec style heads, comp 275DEH, etc) and now that I am almost done I run into a major snag. My year truck uses that big obnoxious steel plate for mounting the accessories that runs down both sides of the front of the motor and bolts to both heads and the block on both sides near the bottom (like where the fuel pump pushrod bolt goes). Well, my new (older) block wasn't drilled and tapped for the plate so it isn't bolted to the motor and now it keeps flexing and moving the p.s. pump away from the block and pitching the serp belt. I thought that big monstrosity plate would be ok without being bolted on in just one place. Boy was I wrong.

My question is, can I drill and tap an older block there or is it thinner and I'll hit water or something? Or can I switch to v-belt accessories and their respective brackets and have it be compatible with my a/c compressor, etc (if so, what is a good donor)?

THANK YOU!!!

 

[skylark]

Can you post pics? I don't recall a block difference, just a head difference. I'm picturing the 4 bolts down low (2 on either side of the crank) and I know I have used a front engine mount plate on early and late blocks that bolt to those 4 bolts.

 

[outalne94z71]

a serp belt turns the waterpump backwards i hope you have the right pump and fan, as far as drill and tap, as long as it has bosses in the block to drill into then you should be ok