3sge ports

[fredk]

I have heard that the gen1 head with the big intake ports doesnt flow as well an the later head with the smaller ones, I might be thinking of the intake manifold and not the head but am I right on this?

[allblackalltrac]

Correct the 1G 3S head has a slightly larger port design than the 2G 3S heads. Speculation suggests that the 2G 3S head with the smaller port design flows better than the 1G 3S head. However it is said that when using the 2G 3S head it is better to swap the exhaust manifolds in favour of the 1G 3S (86-87' Celica GTS) because of the larger port, short runner design. Visa Versa for the 1G 3S head to utilize a 2G 3S exhaust manifold for its small port long runner design. Swapping intake manifolds is not recommended. 1G 3S intake manifolds utilize a long runner, small port design, 2G 3S utilize a short runner, larger port, dual plenum. So as you can see that is the bottle neck is in the designs of the exhaust manifolds hence the reason for swapping them between generations.
Also it should be noted that (2G 3S) the valves have a larger surface area, cams have a longer duration and higher lift and the lifters have a larger surface area as well. It is reccommended that the 2G 3S head is the head of choice for HP potential and aftermarket parts availablility however the 1G 3S head is just as formatable especially because they are more easily available then 2G 3S heads and neither nor one is better than the other in a N/A application.