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Hey all, porting a set of heads of a 94 LT1. Ive attached some pics with related questions. If anyones got answers, advice, or questions themselves please respond away. First timer here so dont expect perfection just lookin to learn. To preface the photos, nothings been buffed and theres still plenty of areas ill be smoothening out, my questions are more about specific areas that may require more additional work. These heads are going on a blown 383 for split track and street use. Thanks in advance! Pic 1: exhaust port is widest at the exit and gradually tapers inwards towards towards the bowl area as shown by the red arrows. Should i widen this taper and have a more consistent diameter from bowl to exit? Pic 2: the corners of the guide boss bulge out as shown in the 2 red circles. Should these areas be ground flush with the port floor?
Pic 3: intake port has a bend on 1 wall. Its widest at the entryy then tapers in, then back out at the throat. Ive opened up the port entry and transitioned it into the rest of the port. Question 1 is should i grind away any more of the curved wall (move red line in the direction of the arrow) to get a more consistent diameter? Question 2 is should i grind away the areas in the blue circles to mantain a similar rectangular shape to the port entry, or do those curves help air flow into the bowl? Pic 4: showing the intake deeper inside. Area circled in red is where that curved wall is at its most narrow. Should this area be ground flush with the port floor? Pic 5: intake port doesnt open to the center of the bowl area. The right line shows the bowl nearly flush with the port. The left shows the bowl curve before meeting the port. Should area near the left line be ground away so the port centerline matches bowl centerline? Or does this offcenter design promote swirl? The bowl wall around the top line is closer to the bowl centerpoint than the wall on the left or right side. Should that be ground so centerpoint to wall distance is equal all around? Pic 6: this is a 2 part question Part 1:i plan on going with larger valves. My seats will get a 3 angle cut (30 45 60) using neway tools. Throats have been enlarged. These seats are stock. I read 2.00/1.56 is the largest valve that fits on the stock seats, but does that mean without cutting? Will cutting allow me to go larger like 2.02/1.60? If yes what size would you recommend? Part 2: shrouding. I know blue area needs to be opened up. Red ? Ive read dont touch. Yellow area unsure if i should touch
LT1 Porting Questions
