www.86garage.com

Hello everyone. So the whole "1620" idea is new to me (I admit I'm late to the party). Long story short, I'm planning to swap a 4AGE into my TE21 and I'm hoping to make this a fairly low-budget build, so I'd like to use mostly spare parts that I already have on hand. I have a good condition 7-rib/42mm block and crank, bigport head, and silvertop rods and pistons. I Googled putting a 16V head on a silvertop block and found out about this hybrid setup.

Like I said, I'd like to keep the build simple so I'm hoping to run the stock bigport ECU. Any chance that will work? I'm mostly worried about the timing curve and detonation. I'm guessing a smallport ECU could work (I do have a smallport distributor and injectors lying around) but I'd have to track that ECU and matching AFM down...

Thoughts? Suggestions? Experiences?

Thanks in advance for any help,
Chris

So, just thinking out loud here: the bigport ECU has a timing curve for lower compression (9.4:1) but was also meant to run on 87 octane gas. With the silvertop pistons and an OEM thickness head gasket, I should be just under 11:1. Running premium gas (which is 93 octane in Ohio), I might be able to get by with the stock timing curve. Worst case, I can back off the timing at the distributor a few degrees. I'm still open to any thoughts or suggestions you guys have.

Thanks,
Chris

I'd recommend a factory thickness head gasket. With a smallport head I suggest at least running the smallport injectors & ecu w/ high octane (93). It wasn't so much of an issue for me as I was carb'd when it came to fueling and for timing I run programmable ignition - on 93. It ran like crud with anything lower than 93.

The smallport was a 10.3 to 1 compression which is just .2 lower than the silvertop.

Thanks for the advice, dr.occa!