rotorhead

i'm considering having my engine rebuilt (12a) and a healthy streetport added. then i started thinking, why not do the same with a 13b? my question is, which would yield the most power, have the highest longevity, be more streetable? i've heard that the 12a's sometimes are more desireable since once ported, they can spin up higher rpm's than a 13b. i want to do this once, and i want to do it right. i already have a 12a to start with, but a 13b would give a better option for turbo in the future. heck... i don't even know if i'd turbo it, but more than likely will go fuel inj at some point. i want/need to crank at least 200 ponies from this car before i'll really be happy.

mar3

iTrader: (8)

I'm a big 12A fan, but the reason the 13B's are heavier is because of their sturdier design and construction. If you've got the money for a 13B into a 1stgen chassis conversion, then do it. It will take the abuse later on better than a 12A. Streeport it with a good exhaust and EFI should pop you in the 180 HP range. Now drop a 100 HP shot of nitrous on 'er. You do the math. It should make you quite happy in a 2500 lb car.

PaulFitzwarryne

You have decided to build an engine with at least 200 hp.

In reality you have four choices
1. a 12a with street port and turbo
2. a 12a with bridgeport
3. a 13bt
4. a 13b with street port
If you had a vote there would be a total diaagreement on what is best. If you had said 180 or 220 bhp my vote would be different.

First changing from 12a to 13b will give you
- more cost for a new core and the changed installation
- heavier weight but a marginal improvement in life
- more capacity giving about 15 hp more
- opportunity to go sraight to EFI if you have the money

The 12a with turbo is a good way to go if you get the installation done right with a good carb and manifold, its relatively cheap and is easily street drivaebl.e

The 12a with bridgeport is the easiest and cheapest solution of all. You could make it on the smaller side and have a degree of streetability. At 200hp it is just this stde of the margin or on it. A 'big' street port might just get you there but for the marginal difference in cost a bridge is better.

The 13bt has many merits as a stock late engine will get you that with EFI and has great long term potential for further modifications. There could be a case for having a small street port done while it is being rebuilt as the cost difference is only about $300 while the engine is apart.

The 13b with street port is a conservative way of going. It will give you the best general results as it would be an easy car to drive in all conditions

All the above solutions assume you are having a good header/exhaust system, upgraded/high performance carb, new fuel pump, etc

Which is best for you is a matter of choice depending on budget and long term use of the car. There are many people on the Forum who have gone down each route and got good results, they will well argue why their choice is best.

My choice for a 200 bhp enginewould be either the 13a with bridgeport, cheapest and still reasonable on the road, or the 13bt the most expensive but having more long term potential. Its your call!

PaulFitzwarryne

Sorry in last paragraph read 12a not 13a its my poor typing on a small laptop.