need help iding a 454 casting #1401544 anf the stamping # near right head is cav129901 , thanks for any help

 

75-87 truck, 4 bolt mains

 

is this considered a tall block or short block truck engine ?

 

if memory serves, short

 

idle too fast or irregular?

 

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<!-- BEGIN TEMPLATE: ad_showthread_firstpost_start --><!-- END TEMPLATE: ad_showthread_firstpost_start -->I have 2 454 G30 vans a '92 (white) & '93 (red 4x4)....stop putting achol in it... put the timming back at 4 deg ( advancing it shows in there comp and you fail ). Both of my 454 put a e-test at: HC allowed 132 at idle is 0 at 15 and 1 at 25 mph, CO allowed at idle 1.32 at 15 its .14 and 0.0 at 25, NO allowed at idle 2208 is 2 at 15 and 152 at 25. What I do before check: change O2 sencer, keep the oil low, get it hot. Open up the tail pipe 3" min so it can breathe. Your loping prob was caused by the cap & rotor, the inside of the cap was torn up so the spark has to travel further makin heat which causes loss of power and irregular idle. Take the air filter out when you go to test for max air going into the block. Both my 454 have passed smog, the 92 this last feb ( just got this one ) but my 93 454 4x4 has passed 5 times doing this ( recemended by the smog place). both are the Tonnawonda motor and have TBI....Both get 11-12.5 mpg on the street and 14-14.5 on the freeway w/ california smog crap on them.....Oh as far as your hi idle the butterfly's wear and dont close all the way( just went thru this w/the red one) put another carb spring on it to pull it back closed. Yes I know TBI dont use springs but add one to your gas peddle linkage it works great......and a cat conveter is a must cause the O2 sencer is further down the pipe, the more crap that goes thru the more your O2 reads and changes the air fuel ratio. The closer you get to FACTORY the more chance you have of passing smog. Then advance it to 11 deg, for more power less mpg. It runs better at 11 but it wont pass smog.
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