I have a 250 inline 6 and i race it at my local oval race track . It is in a 1990 mustang and i would like to know if there is anything i can do to it to improve my power . It is sapose to be stock so i can,t do any mods you can see from the outside of the motor any help would be apretiated
ad power to my 250 ford
- Thread starter racer111
- Start date
shmoozo
Famous Member
racer111":1rw27cmq said:
There are a number of things you could do to increase your engine's power while leaving the engine looking stock on the outside, but you'll need to read through the rules for your racing class very carefully to see just what kinds of things are allowed and not allowed. Does the racing association that controls the rules for your class publish those rules online anywhere?
I don't think they make a double roller timing chain that you can advance for the 250 Jackfish.
Racer can you make internal changes?
Do you have to keep all your emission stuff?
An 1101 carb from a 69 Mustang, port and polish on the head, 3 angle vavle job with a back cut on the intakes, zero decking the block and milling the head to increase compression, 302 valve springs to prevent valve float, gasket matching the exhaust and recurving the distributor are some of the things you can consider.
Racer can you make internal changes?
Do you have to keep all your emission stuff?
An 1101 carb from a 69 Mustang, port and polish on the head, 3 angle vavle job with a back cut on the intakes, zero decking the block and milling the head to increase compression, 302 valve springs to prevent valve float, gasket matching the exhaust and recurving the distributor are some of the things you can consider.
Forgot he had a 250.Compression. 250's suffer from really low compression ratios. The spec says 8.0:1, but in reality its probably closer to 7.5:1 on that vintage engine. Mill the head to reduce the chamber size. You could pick up a significant amount of power that way.
Mustang Boy
Well-known member
well i am pretty sure the intake can be modified pretty easily to accept a one barrel carb from the early 240 or 300 and that will up your CFM and help with your power and what kind of exhaust do you have and what are you allowed to do to your exhaust in the way of headers or open manifold
in know classic inlines makes larger valves for the heads that will help your power out some roller rockers would help especially if you get the full rollers that are a slightly higher ratio and some stiffer valve springs
and see if you can get away with a mild cam that doesnt have too much lope to give it away
you can also get the larger oil filter(i cant remember the part number off the top of my head) and if you are any good at welding you could fabricate a larger sump in your oil pan and some baffles in it to keep the oil on the pickup tube and the extra oil will help keep things a little cooler
and i dont know what kind of accessories you have on the motor but if you can source some smaller pullies from another motor they would help a little
you can also upgrade your ingition system to something with a little more oommpff to get the spark plugs to fire a little harder like a stronger coil and better distributor components
i dont know what your budget is like but i know classic inlines also carries forged flat top pistons that will up your compression as well as decking the block and milling the head along with the usual port polish and 3 angle valve job on the valves
i hope i helped some
in know classic inlines makes larger valves for the heads that will help your power out some roller rockers would help especially if you get the full rollers that are a slightly higher ratio and some stiffer valve springs
and see if you can get away with a mild cam that doesnt have too much lope to give it away
you can also get the larger oil filter(i cant remember the part number off the top of my head) and if you are any good at welding you could fabricate a larger sump in your oil pan and some baffles in it to keep the oil on the pickup tube and the extra oil will help keep things a little cooler
and i dont know what kind of accessories you have on the motor but if you can source some smaller pullies from another motor they would help a little
you can also upgrade your ingition system to something with a little more oommpff to get the spark plugs to fire a little harder like a stronger coil and better distributor components
i dont know what your budget is like but i know classic inlines also carries forged flat top pistons that will up your compression as well as decking the block and milling the head along with the usual port polish and 3 angle valve job on the valves
i hope i helped some
If it were me I would do the following, the mods also vary from cheap to do to expensive.
1) Mill head to raise CR as Mustang Six said.
2) Back cut valves and some mild pocket porting. 3 angle valve job.
3) IIRC stock rocker arms are 1.5:1 ratio. Get some of Classic Inlines 1.6:1 ratio rockers to bump lift at valve a bit.
4) As mentioned recurve dustributor
5) If you are still running the exhaust manifold with the coffee can like light off converter under it dump that for a 1970 ish cast iron single out exhaust manifold.
1) Mill head to raise CR as Mustang Six said.
2) Back cut valves and some mild pocket porting. 3 angle valve job.
3) IIRC stock rocker arms are 1.5:1 ratio. Get some of Classic Inlines 1.6:1 ratio rockers to bump lift at valve a bit.
4) As mentioned recurve dustributor
5) If you are still running the exhaust manifold with the coffee can like light off converter under it dump that for a 1970 ish cast iron single out exhaust manifold.
Howdy All:
Racer111- It would sure help us to help you if we had more information and some details about your budget and goals.
Is this a Pony Class? Dirt or pavement track? How long? What tranny are you using? Are there any rules for the class other then stock appearing? Is there an engine claim rule?
In the mean time know that the cam timing gears on a '78 250 are Advanced for more low rpm torque and emissions numbers- like under 2,500 rpms. If you're planning to use a higher rpm range swap cam gears and chain to a '69 - '71 set.
Moving up to an earlier Carter RBS from 1970 to when it was replaced by the complex Holley 1946. The Carter RBS is rated at 215 cfm. I've never seen a reliable rating on the 1946, but comparing dimensions to other one barrels I'm guessing it at around 190 cfm. A Carter YF from an early '80s 300 might also be a good choice.
The '78 head will have the largest stock valves and hardened seats. If you can't change cams then higher lift, adjustible rocker arms are a good investment. You will find the biggest gains in the head/valve job and increased compression. Bob lined out the plan for the head for you already.
Hurry back with the answers.
Adios, David
Racer111- It would sure help us to help you if we had more information and some details about your budget and goals.
Is this a Pony Class? Dirt or pavement track? How long? What tranny are you using? Are there any rules for the class other then stock appearing? Is there an engine claim rule?
In the mean time know that the cam timing gears on a '78 250 are Advanced for more low rpm torque and emissions numbers- like under 2,500 rpms. If you're planning to use a higher rpm range swap cam gears and chain to a '69 - '71 set.
Moving up to an earlier Carter RBS from 1970 to when it was replaced by the complex Holley 1946. The Carter RBS is rated at 215 cfm. I've never seen a reliable rating on the 1946, but comparing dimensions to other one barrels I'm guessing it at around 190 cfm. A Carter YF from an early '80s 300 might also be a good choice.
The '78 head will have the largest stock valves and hardened seats. If you can't change cams then higher lift, adjustible rocker arms are a good investment. You will find the biggest gains in the head/valve job and increased compression. Bob lined out the plan for the head for you already.
Hurry back with the answers.
Adios, David
I would like to thank everybody for the info it is all vary helpfull .
as for the track i race on it is a 3/10 of a mile D shapped oval paved .
There is no engine claim rule . The class is hobby stock all cars have to have an inline six .There are chev and ford the ford do dominate but thay wont share there secrets with the other drivers . There are no emission things on the motor there is just what you need to make it run . I don't even have powersteering on the car. The head porting and the valve job
i can do myself so that is no probleum . What cam would you guys suggest we deal with web cams on a regulare basses so if anyone nowes if web has a good cam for a 250 could you let me know thankes
as for the track i race on it is a 3/10 of a mile D shapped oval paved .
There is no engine claim rule . The class is hobby stock all cars have to have an inline six .There are chev and ford the ford do dominate but thay wont share there secrets with the other drivers . There are no emission things on the motor there is just what you need to make it run . I don't even have powersteering on the car. The head porting and the valve job
i can do myself so that is no probleum . What cam would you guys suggest we deal with web cams on a regulare basses so if anyone nowes if web has a good cam for a 250 could you let me know thankes
Patrick66
Famous Member
http://www.classicinlines.com <cams and anything else you'll need.
if it just has to have a straight six, why not put a 300 in it. i know i saw someone do it, so i know it can fit.
if it just has to have a straight six, why not put a 300 in it. i know i saw someone do it, so i know it can fit.
Mustang Boy
Well-known member
so are you restricted to using any one barrel carb or only the stock one barrel because if you are allowed to use any one barrel i would do some research on here and find out what the largest cfm one barrel is that is easily obtained and make some sort of adapter to adapt it to the stock log head
and since there is no engine claim rule i am guessing that the motors only have to appear to be stock which means you can do virtually anything you want to the internals and valve train and what not and if this is true i would definitely be taking a look over at classic inlines site and going crazy
and since there is no engine claim rule i am guessing that the motors only have to appear to be stock which means you can do virtually anything you want to the internals and valve train and what not and if this is true i would definitely be taking a look over at classic inlines site and going crazy