Jenvey throttle bodies on a TC - throat size?

[jono]

I have the opportunity to purchase a pair of 2nd hand Jenvey TB's dcoe pattern for use on my TC.

My TC head has inlet ports at the flange face of 42.5mm whereas the second hand tb's I am considering are 40mm on the mounting face and 45mm on the inlet throat. I can obtain tb's new with a 42mm opening size on the mounting face which would seem to be better matched to my head,

The question is, would a difference of 2.5mm make any significant difference in flow characteristics and therefore power/torque? If not then I am tempted to have a go at the second hand bodies. If on the other hand there will be a meaningful difference I may as well spend a bit more and get new tb's which are better suited to my head.

The engine spec is + 60 overbore, sprint spec inlet valves and larger exhaust valves, QED 360 cams and a TTR fast road exhaust manifold and some mild porting. I am looking for around 135/140bhp with good torque.

cheers, Jono

[rgh0]

With your spec engine I dont think you will loose anything in terms of engine performance with the second hand throttle bodies

cheers
Rohan