just revisiting some power increase ideas. my 450slc drift car is great. i beat the snot out of the stock 4.5 and haven't had any failures. i had a head gasket oil leak from the outside at one of the galleys i guess. swapped for a fresher long block while i had it out changing the clutch disc.i just pulled a 560 ex manifold and was shocked by how much bigger the ports are. so i started thinking about 5.6 heads ion the iron block again. bigger chamber is no good so im wondering about 4.2 heads. they have the same size intake valve but larger ex valve than stock 4.5 heads. im guessing the 5.6 inntake valve wont clear the 92mm bore. i want to know if they have smaller chambers than the 5.6 heads. i want to rebuild and port a set of heads this winter so im trying to start with the best option. i have 3.5 3.8 4.5 d and kjet and 5.6. i still have the turbo idea so thats why the 3.5 makes me think twice because of too high compression. i want to stick with a stock bottom end so if i do scatter it hopefully the heads are ok.
listen to the 4.5 with straight 2.25 pipes sing!!
https://www.youtube.com/watch?v=NjvNVXF8LsY