Low rpm 390 stroker advice - Page 2 - Ford Muscle Forums : Ford Muscle Cars Tech Forum
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post #16 of 90 (permalink) Old 08-25-2018, 08:40 AM Thread Starter
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Re: Low rpm 390 stroker advice

Yeah. I think it will be a good looking engine. Black intake, aluminum heads, etc. the engine already has a few new things on it. I attached a few pics but there’s a few more in another thread I started...
https://www.fordmuscleforums.com/gal...l-upgrade.html
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post #17 of 90 (permalink) Old 08-25-2018, 08:44 AM Thread Starter
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Re: Low rpm 390 stroker advice

Something we didn’t discuss is exhaust. I have fpa shorties, xpipe, flowmaster tailpipe kit, and dynomax freeflowing mufflers. Exhaust is 2.5” mandrel bent compared to 1.5” from factory. Good enough?
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post #18 of 90 (permalink) Old 08-25-2018, 12:19 PM
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Re: Low rpm 390 stroker advice

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Originally Posted by lsugymrat24 View Post
Something we didn’t discuss is exhaust. I have fpa shorties, xpipe, flowmaster tailpipe kit, and dynomax freeflowing mufflers. Exhaust is 2.5” mandrel bent compared to 1.5” from factory. Good enough?
Yep. I have been going 3 inch on everything big, but 2.5 mandrel bent is absolutely enough for the engine size and rpm range. I wouldn't spend a penny more on the exhaust

70 Sportsroof, 427 FE/489 cid, TKO-600, 31 spline 4.10, A/C. modified Mass-flo EFI/reprogrammed A9L/CnC ported Victor.
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post #19 of 90 (permalink) Old 08-25-2018, 02:54 PM
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Re: Low rpm 390 stroker advice

What is the performance goal for this motor, mabe that of a stock 460?

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post #20 of 90 (permalink) Old 08-25-2018, 04:11 PM Thread Starter
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Re: Low rpm 390 stroker advice

Thanks Ross. That’s great news on the exhaust because I already own it. Lol

Iowan, the goal is more performance than the 428cj while still keeping my stock 3speed cruiseomatic and enough vacuum for the power steering. The custom cam from Lykins outperforms the cobra jet cam across the board (more overlap, more lift, more duration, more advance) but I shouldn’t need an increased stall speed to run it which is good bc there are few performance upgrades for my transmission. I’ve decided on using the 390 block and boring 30 over and stroking to 4.25 for 445cubes so that alone smokes the 428cj. Ed heads should flow better than imported stockers. Exhaust is 1” larger than stock also. Hoping for 400hp out of the stroker while keeping good street manners (Will never see the track). I think I will get there but I’m open to suggestions.
Some more of the items I’ve decided on are in the original post - 3.50 gears, performer rpm intake, edelbrock heads, etc.

I once had a 1971 460 Lincoln motor in a 1968 f100 and always wanted one in a car. Guess this is as close as it gets

Last edited by lsugymrat24; 08-25-2018 at 08:46 PM. Reason: Better info on cam etc
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post #21 of 90 (permalink) Old 08-25-2018, 09:08 PM Thread Starter
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Re: Low rpm 390 stroker advice

found these 460 factory cam specs. Looks like my cam should outperform it.

1970 429/460 passenger car engine (incl. Thunderjet) Cam Specs:
256°/270° @ SAE
193°/206° @ .050"
.253"/.278" lobe lift (.443/.487 valve lift)
110°/116° lobe centerlines - 113 LSA

Not sure how the heads compare to the 460. Didn’t the late 60s 460 motors have around 375hp and 460ftlbs at 10.5 compression while the 428 Cobra Jet had around 335hp and 445 lb-ft at 10.6 compression? I think my 445 idea will beat both of these and run lower compression for today’s pump gas

Last edited by lsugymrat24; 08-26-2018 at 06:30 AM. Reason: 460 and 428 specs
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post #22 of 90 (permalink) Old 08-26-2018, 06:29 AM
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Re: Low rpm 390 stroker advice

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found these 460 factory cam specs. Looks like my cam should outperform it.

1970 429/460 passenger car engine (incl. Thunderjet) Cam Specs:
256°/270° @ SAE
193°/206° @ .050"
.253"/.278" lobe lift (.443/.487 valve lift)
110°/116° lobe centerlines - 113 LSA

Not sure how the heads compare to the 460. Didn’t the late 60s 460 motors have around 375hp?
So, I would take Iowan's question in context of your exhaust question not just a cold performance question and answer "Likely a little more but similar to one with a set of headers and good intake/compression"

The reason is, the 460 will have more cubes, better heads, but less cam, but will still make power in a similar RPM range, especially if it's an early one. Keep in mind, the 460s have a much better head design that will equal or outflow your Edelbrocks out of the box, so it "needs" less cam

So in that light, yes, it's about like an early 460 and a 2.5 mandrel bent system will be plenty, if you were going higher RPM, a 445 or a 460 for that matter would start wanting more exhaust.

However, your pic almost looks like to the dumps it's 3 inch then 2.5 after, is that correct? If so, if/when you go to the strip, open the dumps and let her breathe

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post #23 of 90 (permalink) Old 08-26-2018, 06:40 AM Thread Starter
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Re: Low rpm 390 stroker advice

Hmmm. Good question. I will have to go look at the xpipe again. I think it’s 2.5” all the way. Was thinking about electric cutouts for driving in and out of car shows. Pure vanity. Lol
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post #24 of 90 (permalink) Old 08-26-2018, 08:57 AM Thread Starter
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Re: Low rpm 390 stroker advice

with no shift kit or aftermarket stall converter and with 5500rpm max and only 3.50 gearing in a huge car, I was just thinking of street use only. You mentioned using the cutouts for at the track. Would you think a car with this setup is worthy of taking to the track?
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post #25 of 90 (permalink) Old 08-26-2018, 11:28 AM
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Re: Low rpm 390 stroker advice

Just out of curiosity what are the cam specs you plan on using?

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post #26 of 90 (permalink) Old 08-26-2018, 12:52 PM Thread Starter
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Re: Low rpm 390 stroker advice

I don’t want to get too specific because Brent lykins custom sized it for me in order to stay with stock transmission. It pretty much follows what him and Ross have suggested in other threads. I don’t think he would be too upset for giving conceptual info and not the specific lobes or numbers...
Around 220 degrees intake duration at .05 lift,
a small split between intake and exhaust to help with scavenging,
under .5” total lift,
more overlap than 110 lsa,
and enough initial timing to almost worry about hitting valves.
The idea was to get close to the Comp XE262H but without slamming valves open and closed, without the valvetrain noise, and with more overlap and with more timing

Last edited by lsugymrat24; 08-26-2018 at 01:07 PM.
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post #27 of 90 (permalink) Old 08-26-2018, 02:42 PM
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Re: Low rpm 390 stroker advice

That's anemic for a 445, a stock 289 can handle a cam with 218/[email protected] with a stock converter. It was a Ford cam and Ford referred to it as a torque cam.
You're going to have 156 CID more than the 289 it could easily handle ten more degrees of duration at 50.

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Last edited by Iowan; 08-26-2018 at 04:06 PM.
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post #28 of 90 (permalink) Old 08-26-2018, 03:07 PM
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Re: Low rpm 390 stroker advice

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That's anemic, a stock 289 can handle a cam with 218/[email protected] with a stock converter. It was a Ford cam and Ford referred to it as a torque cam.
If you just compare .050s, Ford used to use 114 or greater LSAs, this is much tighter and will use overlap to his advantage with a 108 spread. The duration is pretty close to a stock CJ cam, but with 52 degrees of overlap instead of 46, so it does seem small, and was originally planed for a 390, but with the good heads and intake it'll pull real hard for the use

I would say though, be sure you talk to Brent about compression and intake centerline when you buy your stroker parts, my hunch is that he'll probably have you retard this cam since you are now going 445 instead of 390

I'd likely put that cam on a 108 ICL in a 445 with a true and measured 10:1 compression, if it's 9.5, you could go as early as 104, but I think the 445 will like it a bit later and 10:1

I think it'll peak around 5000-5200 depending where cam centerline ends up, certainly no drag motor, but it'll make more HP than an original 427 with the manners of a stock 390 and a nice little lope at idle

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post #29 of 90 (permalink) Old 08-26-2018, 03:21 PM Thread Starter
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Re: Low rpm 390 stroker advice

not going to argue against that which is why I didn’t consider taking the car to the track. Guess it all depends on your goals.
I am aiming for street performance better than the cobra jet but want to keep my cruiseomatic which is only rated at 1800rpm with the 390. Every thread and cam manufacturer website says anything with more duration needs at least 2400 rpm stall which I don’t have. I don’t have all my numbers handy but Even though my cam is fairly anemic compared to other performance cams out there, I think the 428 cam was only 211 degrees intake and .475 lift with a huge lsa around 116 and way less timing? If so, my cam beats it in all aspects
My only concern is whether the valves will hit if I go with the extra stroke and all the early timing. Ross, at 4.25 stroke, what’s the earliest timing you would build into the cam? That’s the ICL, right?
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post #30 of 90 (permalink) Old 08-26-2018, 03:24 PM Thread Starter
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Re: Low rpm 390 stroker advice

I see you beat me to the punch. Thanks. I will have to retard the cam if I use the one i have
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