What should a decent built 318 built to a 390 stroker make for hp? I know there are a million variables but average. Performance heads and I believe a 750 or 850 Holly double pumper….. It will go on a dyno but not now. I bought it built so I’m curious, it revs fast and sounds awesome! Any thoughts would be appreciated, thanks
Small block question
- Thread starter bamech68
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Any idea what cam and pistons?
Thanks. Nice Barracuda
harrisonm
Well-Known Member
TOTALLY depending on cam and pistons. However, I would say that with 10.5:1 and a medium cam like a Comp XE 268, you'd be at about 450 HP. Different cams would get you a lot higher. That is just my guess.
I'd guess 375 but the cam will determine where it makes power. You can make 450 at 6k or a flat 350 to 400 with a less aggressive cam and pick up a bunch of torque. Gearing and intended purpose should dictate YOUR cam choice not what somebody else put in it.
You guys kill me on these horsepower guesses. There isn’t enough info on this to even post up a guess. Lots of wishful thinking
thats why i gave a wide range
if it doesnt make 425 from a stroker might will have built a 318
Professor Fate
Push the button, Max...
Not enough info to hazard a guess, but here's a FACT: You're going to grenade your transmission if you don't sort out your kickdown linkage. The pictured adjustment is WAAAY off.
I'm willing to bet that throttle linkage isn't opening the carb all the way, either. The geometry looks off.
Just mentioning it for what it's worth; take it or leave it.
That looks like a 600 cfm vacuum secondary. At least it looks like the one I had in the 70's. Could be a different ball game now.
I’m asking for advice and anything you guys are willing to share, I will take and leave nothing. I’ll look into the linkage, thank you for offering your advice! The trans is the only thing not worked so I’m expecting it won’t last. What would you recommend?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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IDK where that fuel line is going but I haven't seen that before. And the last time I checked, my closest racetrack would not have let me onto the track like that. Not knocking your combo, just saying.
My guess is 333 hp and 433 ftlbs, I dont care what cam is in it, a guess is a guess, lol.
I highly recommend a compression test and
an audio clip of it idling at 14* to 16* @700rpm.
And I agree that the entire throttle mechanism needs to be re-engineered.
For WOT power at the track, yeah you'll need a 750 or bigger carb, but on the street that lil bugger will be fine. For a lil more excitement, ie instant tirespin, a DP carb would provide lots of giggles. If you gotta buy something, I recommend a spread-bore on a spread-bore intake, with some kind of Secondary control.
To stay out of trouble in the turns, My 68 Barracuda is wearing 295/50-15s. Anything less and she kept spinning out; not good in traffic.
My guess is 333 hp and 433 ftlbs, I dont care what cam is in it, a guess is a guess, lol.
I highly recommend a compression test and
an audio clip of it idling at 14* to 16* @700rpm.
And I agree that the entire throttle mechanism needs to be re-engineered.
For WOT power at the track, yeah you'll need a 750 or bigger carb, but on the street that lil bugger will be fine. For a lil more excitement, ie instant tirespin, a DP carb would provide lots of giggles. If you gotta buy something, I recommend a spread-bore on a spread-bore intake, with some kind of Secondary control.
To stay out of trouble in the turns, My 68 Barracuda is wearing 295/50-15s. Anything less and she kept spinning out; not good in traffic.
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All good, that’s why I’m asking. She deserves to be correct!
And I’m going to get her right!
So I bought at in my opinion at a price point that reflects her for what it is, it’s been restored and started out nice. It’s not perfect but nice, the top is new and everything works, Needs a little attention and that’s what will happen. I’m new to old cars but always liked them. Before this I bought an all original other than paint a 49 4100 dually(and still have) not Plymouth but cool….. I was brought home in this world in a 74 318 Duster so before long I’ll get one of those as well….
Thank you for all of that input! It has 17’s all around and looks good. But the 295-50’s would bite the road nicely! I’ve driven it less than a mile and it ***** and gets!!! I couldn’t be happier with the purchase but like I said it needs a little love and that’s why I’m reaching out, thanks again!
The thing your kick down is connected to is the throttle stud. The kick down should be connected to it on the outside, and the throttle cable connected to the part on the inside (next to the carb where your kickdown is connected now). It looks like something is put in the slot of the kickdown - That is probably because the kick down is still one for the original 318 two barrel and was never corrected when converted to a 4 barrel - it's too short. Edelbrock makes a piece that goes between the two sections of the kickdown rod to correct for that.
Here is a picture of a correctly situated linkage:
Here is a picture of a correctly situated linkage:
Appreciate that! I think after a bit of fine tuning it be where it should. You guys are awesome with sharing knowledge! It’s definitely not falling on def ears! She runs good and sounds good but getting everything correct I think it will represent the brand just fine
Great catch on the kickdown!
Repair/fix that before you drive it anywhere!
@CUDACOX has a 318/390, in his 68 cuda, he may chime in.
Repair/fix that before you drive it anywhere!
@CUDACOX has a 318/390, in his 68 cuda, he may chime in.
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