Need advice on heads

[89 tercel racer]

I was wondering if a 4AGE AE101 20 valve head will fit on a 16 valve block. If the head doesn't fit what would I have to do to make it fit. To me it only looks like the pistons have to change maybe. I only say this because i have a spare 4AGE 16 valve block.

[freakinbox]

well I know this will be one of the first questions. I am not sure if it will. But you do know the 4a block underwent some mods to it through the years. so identifying the engine first will help you.

[thespud]

It will fit, but it will probably be cheaper and easier to get the whole engine. For one, the Compression ratio on a 20v ST it 10.5:1 and BT is 11:1. Depending on the gen of the block, it is around 8:1 on a 16v.

The second problem is the conversion from MAP to AFM in the ST. The third is the ECU. The 16v ECU will not run the 20v Head. The fourth then comes with the wiring. The 20v head and ECU will need the 20v Wiring Loom. The next issue is fairly simple: the 20v has a knock sensor on the back of the block, the GE's and FE's (unless it is a 7A, or a GZE) dont have one, so this is also a problem as the 'safe' fuel map on the 20v sucks.

So in other words, unless you are building a 7A-GE 20v Hybrid, get yourself a complete engine and wiring loom... Will be much easier...

[rezzle]

You can do it but it isn't worth the exta cost. It really wasn't the head that gave the 20v the extra hp it was the high compression + Japanese high octane gas and the ecu.

You would be better off looking for an early gen bigport 16V head or just sending out the one you have to a local - reputable - rebuilder for a rebuild + port and polish. Check with the local sports car clubs and see who they use.
Edit:just read you only have the block ... doesn't matter much though the 16V head works just fine and are easier to find.

[Flashmn]

pistons, lower crank wheel for timingbelt, tensioner wheel,