24lb questions

BKM48198

5 Year Member
Jun 7, 2008
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Ypsilanti, Michigan
How much HP will 24lb injectors be good for? I already have 24lb injectors and mass air meter, a 65mm TB and an explorer intake and am looking to get another engine because I am starting to get lower oil pressure after the engine warms up. I want to keep it fuel injected rather than switching to a carb. Any advice on 306, 331, or 347 for an old guy that won't race the car and really want a dependable engine with more power?
 
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7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
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If you have the money, the extra torque of a 347 will be fun. A 302 can be made plenty fast for the brakes and chassis, but the extra cubes can bring the power band down some into the more street friendly range. I am not sure why I’d build a 331 instead of a good 347 kit.
Money, transmission, use, power goal and your tolerance for a squirrelly engine are going to factor into your best answer.
 

BKM48198

5 Year Member
Jun 7, 2008
373
28
49
Ypsilanti, Michigan
If you have the money, the extra torque of a 347 will be fun. A 302 can be made plenty fast for the brakes and chassis, but the extra cubes can bring the power band down some into the more street friendly range. I am not sure why I’d build a 331 instead of a good 347 kit.
Money, transmission, use, power goal and your tolerance for a squirrelly engine are going to factor into your best answer.
Will the 24lb injectors and Mass air be enough for a 347?
 

BKM48198

5 Year Member
Jun 7, 2008
373
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Ypsilanti, Michigan
24 lb injectors are just not quite enough for 400HP....I would go for 30's
I'm not looking to make 400hp, I want to get an engine that the 24's will support so I don't have to replace the injectors and mass air I already have. I'm almost 59 and have a 90 Mustang GT I bought in 89, this will probably be the last engine swap I do on the car and want to get what will work with parts I already have, my TFS 170-58 heads and stage 1 cam might end up getting sold if I can find a complete engine for about $5k, I want more power than the stock engine had but will never race it, mine doesn't have to be the fastest car around, just a good looking one I can depend on.
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
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You could easily be driving this for another 20 years. Many of my regional band members did not retire until near their 90th birthday. There’s no need to sell yourself and the engine short for the cost of the injectors and MAF. :)


There are all kinds of calculators on line for this. And I am sure I read a tech article by @jrichker, @a91what or another tech guru.
Based on your goal of driving, not 400 Hp, I bet 24 lb will be fine. I’m not sure you need to go to the expense of the striker engine to have a fun, drivable car with 24 lb injectors. A 325-350 Hp 302 in a Fox chassis will be lots of fun on the street.
Those should be good heads. Have you already had them on a 302?
 

BKM48198

5 Year Member
Jun 7, 2008
373
28
49
Ypsilanti, Michigan
You could easily be driving this for another 20 years. Many of my regional band members did not retire until near their 90th birthday. There’s no need to sell yourself and the engine short for the cost of the injectors and MAF. :)


There are all kinds of calculators on line for this. And I am sure I read a tech article by @jrichker, @a91what or another tech guru.
Based on your goal of driving, not 400 Hp, I bet 24 lb will be fine. I’m not sure you need to go to the expense of the striker engine to have a fun, drivable car with 24 lb injectors. A 325-350 Hp 302 in a Fox chassis will be lots of fun on the street.
Those should be good heads. Have you already had them on a 302?
They are on my JY Explorer engine with the TFS stage 1 cam, money is more the issue because my wife has been dealing with bladder cancer and has had 3 surgeries in the last 1.5 years and another checkup next month, don't want to spend alot on other parts right now, I'd rather get a better bottom end that will last and work with what I already have and just be able to drive it to work daily and go on 3-4 hour trips without problems. I want low end torque more than high end HP.
 

KRUISR

5 Year Member
Apr 16, 2015
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Then why not just have the bottom end rebuilt by a reputable shop. With the heads, cam, intake, injectors you already have you should be in the 325-350+ HP range. Lots of fun on the street with a strong foundation.
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
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I had a 347 for a few years. It was great but the 331 is a little less hard on internal parts. They are about the same money to have built. My 331 is turbocharged so no way to compare. I can say that the torque of the 347 lit the tires up with ease. I didn't have any internal issues with the 347. The newer designed pistons put the pin lower allowing better piston movement.

A good 306 would be nice on the street. The key is what you want out of it. With the 170- 58 heads I'd go with a healthy 306 with the TFS stage 1 cam and 24lb injectors. As displacement increases camshafts tend to get a little more subtle. The same cam in a 302 won't act the same in a 347.

That 306 should put you somewhere around 260 to 270hp....and a bit over 300ft. lb. torque. That's within reasonable t5 and chassis limits.

I'm not an engine dyno guru. This is a proven combo over the years. Fun street strip car that's dead nuts reliable.
 
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