BIGMAC9940

hey guys i am planning on starting a motor build so that when i graduate college i will have a fresh motor to drop in after i have put many more miles on the motor. i know that these motors are 250k motors, but it is a good excuse to build a motor. so i have a lincoln mark viii motor sitting in a donor car that i can use or are there any better ideas. here are the parameters, 1. this will be a daily driver so mpgs has to be considered, 2. i would like a pretty stout motor, 3. i would prefer to stay away from f/i not that there is anything wrong with it but if you smash the gas with f/i your gas gauge falls quickly 4. i am a college student so cheapest route possible, this will be done over time though so i can spread out the cost. i was thinking take the mark viii motor and make it a high compression n/a motor, which would yield better fuel economy and better power correct? i know that big power and best mpg doesn't work well, but if you can keep your foot out of it they should. look at the zo6 it is 500hp and gets 24mpg highway i know that isn't awesome mileage but i could live with it considering the power. thanks in advance for all who reply.

SeeingRed

If you want MPG, go with a 4v motor, but have fun spending $$$. The only way you're gonna make a mean *** n/a 2v is if you go big bore and high compression, which is expensive. The machine work alone for a big bore is gonna run you around 2k for all of the cylinder boring, the honing of the sleeves, the cost of the sleeves themselves, etc. Even with that and monster cams like Comp 270s, you're only gonna be looking at the mid 300 range to the wheels.

I would recommend going with a .030 over bore, forged internals of course, port the heads as much as you can (Livernois Stage 3 port would be awesome, but it's pricey), some good, mild cams like Comp 262s or something similar, some gears, and a PI intake. With a combo like that, you'd probably be looking at upper 200s, lower 300s to the wheels and very streetable/reliable with good gas mileage.

Mustang_NTriangle

If you smash the gas on a high compression v8 motor with cams you are going to lose mpgs period.

BIGMAC9940

i understand that if your foot is in it you will lose mpgs, my goal is to build a motor that when cruising you get good mpgs but when you wanna jump on it the motor comes alive. right now my car runs really good with mods in my sig and i get 19mpg city and about 25mpg highway, i would like to get the same or better mileage but have more power. so my thought was a higher compression motor.

MU71L4710N

you said you don't want FI because when you put your foot ont he gas you drain gas. horsepower is air and fuel nomatter which shape it comes in. a car with some aggressive cams and ported heads is going to be a terrible daily driver and will drain more gas daily driving than a supercharged car would staying out of boost. so infact a supercharged car will get better overall mpg than a car with ported heads and cams.

what are your realistic horsepower expectations?

BIGMAC9940

i would like to see 300 or better to the wheels. i know that is possible with a well built motor or f/i. if f/i can yeild decent mileage then i will go that way, i would like to see some people who are getting the mileage with the f/i. i guess i have been arou,d pushrod guys to much who say the only way to get fuel economy if hign compression and no forced induction. wouldnt the f/i require a bigger fuel injector than a high compression motor to supply fuel for the f/i?

SeeingRed

With dual 255 LPH Walbro pumps, 60lb/hr injectors, and a ProCharger D1SC on 17PSI of boost, I could get 16-18 MPG in town and 22+ on the highway if I stayed out of boost...and that's with a T-56 and 3.73 gears.

It'll take quite a bit to get a 2v motor above 300 RWHP. That's not something you can do with just cams, intake, and exhaust. To get that number, you'd need either some super hogged out heads or new heads, aggressive cams, etc...2v motors aren't good to make big numbers n/a without spending some serious coin.

SeeingRed

Duplicate post

teej281

just build that mark 8 motor. you can make some pretty good power with 4v heads n/a. What i say is that you go with the n/a route since you have the 4v motor as the donor motor and just get the wiring harness as well to make the swap. What i suggest that you do is forge the bottom end, get the compression over 10:1, get some nice cams, and get some 03 cobra/mach 1 heads and you'll be in the mid/upper 3xxrwhp range n/a, still only need a 24lb or 30lb injector, and then you can put on a shot of spray whenever you want more power. But i'll put it this way...a supercharger on a 96-98 GT will get you to like 330-350rwhp and then you gotta start getting into cams and intakes to make 400rwhp. So i say high compression. Plus 4v's just sound badass revving to the moon. A lot of people wont agree with me...but this is just my opinion.

BIGMAC9940

thanks for the input so far to all. seeingred the info on your car and mileage helps a lot, what kinda power are you making? i wouldnt be going as high on boost probably 10psi tops on my current 03 motor if i went that route. but if teej281 is right about the power output of the 4v na high compression i would probably go that route. i would image it would be better on fuel, and i already have everything except internals. as far as tuning would it have to be dyno tuned for a higher compression motor? i know it would for fi.