4a Head on 7a Block???! Options

[Dennisj1]

Hey Guys just looking for some info on a combination of head and block.

Where I'm from we have a few cars with 4afe/4agze running between 13 and 14 seconds on the dragg strip which I find verry cool.

So, I was wondering if my 7afe with automatic transmision can be swapped with the following: 4a (black/silver top) 20 valve head on my 7a block and a manual transmission.

1. Can I first swap the head only and leave the auto tranny?

2. With some modifications like changing sparkplug, intake, injectors, tranny etc (except turbo and nos) would I be able to run between 13/14 seconds on the dragg strip?

3. Would this conbination cost a lot of money?

4. Is the combination of 4a head on 7a block called frankenstine?

Just looking for some ideas, appreciate the help. THX!!!

[95CelicaST]

And there might be an all motor 4A that runs a 14.5, but not a Celica. It comes down to power/weight ratio. I'm sure a 4A put in a go kart can hit insane 1/4 mile times, but only because of the power/weight ratio being really high.


A 130WHP 4AGE (silvertop, for closest power example) in a 2800lb Celica (I'm being awfully generous. This would require a bit of weight reduction) has a power to weight ratio of .0464, which might be better than a stock 7AFE Celica, but the same motor in a 2300lb (curb weight, per OEM specs) AE86 Corolla has a power to weight ratio of .0565, which doesn't look like much change, but it's actually quite a bit. The closer that number is to 1, the faster you're going to be.

Take another example - a Lotus Exige. Same 2ZZ-GE motor from the 7th gen GTS, only the Lotus weighs in around 600lbs less. This is why a 180hp 1.8l all motor car can keep up with much bigger, higher HP cars. Like a 350Z. On paper the 350Z is faster, due to higher HP, but in reality it's power to weight ratio is substantially less, making it slower.

Lotus Exige - .0906
Nissan 350Z - .0638


So in a long winded answer - it doesn't matter what others pull on the strip with the same motor. You're heavier than them, so you will be slower.

[SwissFerdi]

2800lb Celica (I'm being awfully generous. This would require a bit of weight reduction)

I know my motor's different, but why? Mine weighs 2409.