I am going to build a new engine this winter and I am pretty new at this thing. I have some goals that I would like to meet and don't know how realistic they are. I have a 1990 coupe.

Not in any particular order of importance:
1. Streetable.. I want it to be a daily driver.
2. Reliability - I want to drive it for 200k miles.
3. Decent mileage, I would like to keep it over 20mpg, maybe even 25mpg while crusing down the freeway.
4. Cost - While this one is of course going to be pretty high, I am thinking between 8k and 15k, but cost is always on my mind.
5. I would prefer to keep the exhuast as quiet as possible, but not if I am going to lose a noticible amount of power.
6. Emissions compliant... I don't think that will be remotely possible.
7. Be able to beat 99% of rice burners and other cars out there.
8. Run on pump gas.

The most important 4 considerations are number 1, 2 and 7 and 8.

I am thinking of starting with a dart 400ci block and stroking and boring it to 427ci. I know to get the power I want I will need a turbo or supercharger, but which one I don't know yet.

I am thinking 225 afr heads, not sure of the intake or cam. Forged pistons... I want it to be bullet proof.

I will probably build the engine with a turbo or supercharger in mind, but because of the cost I will run it without the turbo or supercharger until I can afford one. I know that means a lack of power at first since I am going to go with a lower compression setup (to maximize the potentionial of the turbos or supercharger down the road).

I also realize I am going to have to beef up the drive train, and I will do that down the road as I start building power.

I may also want to toss some NOS for the track or other situations

Any opinions or thoughts? How much power is possible on pump gas? I guess im shooting for in the neighborhood of 600 to 800 hp and/or tq, but more is always better.

 

well.... Dart Block to start, forged crank, forged rods, coated forged heavy duty pistons, dish volume to suit compression ratio desired and cylinder head chamber volume. thats the easy part.

first let me ask do you have E85 available to you? if so this is a key important factor.

displacement.. I would aim big cubes, 427 sounds like a good start since you are adamant about pump gas. this will make more power per pound of boost used. heads sound alright but I may even aim a little bit bigger and start looking at an 18* head since you will have that option on a dart motor and a 1990 style car.

Brodix makes some good heads as well as trickflow and AFR of course.. that alone will put you in a new realm of power making potential.

for that setup a rear mount turbo system would work fairly well and I would convert the motor to a dry sump oiling system and use one of the vanes of the oil pump to return oil from the rear turbo to the motor.. thats one way to go turbo relatively easy.

the other is a fulkl blown fabricated front mount turbo system which is wuite a bit more entailed and usually a tremendous amout more expensive.

Blower is a good way to go with the help of the existing drive system upgrades.. ysi trim vortech or D1SC-F1R blower would make some very nice power and most likely be the least expensive route to take.

theres some starter ideas.. I am sure several others will chime in with some help as well..

PS... you can drive anything 200k miles.. you may just need to replace a few parts along the way..lol as for MPG.. not unrealistic with a perfect tune but at some point you will have to come to terms that power making isn't exactly a fuel efficiency friendly endeavor.. your gonna need to get a little bit realist with it or buy a car like the 85k C6 ZO6.. it was engineered to do those things only with a little less power then you are looking for.

use it as a template for parts.. or maybe buy an LS7 crate motor and run it as is until your ready to boost it then swap the hyper pistons to low compression forged ones!

CHris

 

Are you running a stick or an auto? The cam is going to make or break your fuel economy mark. Since you are planning on going forced induction you'll want to go with a smaller cam with less overlap. That will help out a bunch.

How many RPM's are you planning on spinning this thing?

I would also recommend a supercharger setup. It will be the least amount of headache and cost. It won't as good on power, but if you are running a 427 then 10 psi should put you well into your goal power range.

I would recommend getting heads that flow well and have large combustion chambers. If you can get a 9:1 compression with flat top forged pistons you will be better off than having a smaller chamber and dished pistons. The more meat on a piston the better it will withstand a beating. Try and keep the ring lands low on the piston if you have that option.

I'm not too farmiliar with the 427ci, but remember there is a replacement for displacement, its called boost So don't get hung up on the displacement if you can build a more reliable 400ci engine. Ask LCvette what he did with his little 355ci boosted motor.