[camino_man]

i was wondering if i could put 2.02 intake valves in my 73 sbc 400. it has the stock heads. also if i make the intake valves bigger, should i increase the size of the exhaust valves?

[lluciano77]

You could fit 2.08 valves if you wanted to. Unless you are running nitrous or forced induction a 75% exhaust to intake flow ratio is optimum. Valve size doesn't change that by itself, but it can help.

[firechicken383]

Yes, you should put in 1.6 exhuast valves if you are putting in larger intake valves. In fact, if you could just do one, I would put in the bigger exhaust, ALWAYS. A stock head is so bad on exhaust flow anyway it really needs some help.

[troy-curt]

Yep, a lot of people never think about the exhaust valve, but a larger one will do more good than a larger intake, especially with a good blend job.

Troy

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[lluciano77]

Stock heads like additional exhaust flow. Aftermarket heads generally like more intake flow.

[mikeweyman]

If the're 882 castings go with 2.02/1.65 have the head shaved down .020 and use a .028 head gasket. ported, exhaust ported and polished,gasket matched, clean up the short radius, and you'll toss an easy extra 50 h.p. or so. mike
dont forget to unshroud the intake valves as they will be close.