CA emissions legal 460 build - 460 Ford Forum
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post #1 of 5 (permalink) Old 09-11-2019, 07:29 AM Thread Starter
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CA emissions legal 460 build

Looking for some piston and cam advice, as well as any other suggestions.

I'll be rebuilding the 460 out of my fathers '77 f250 Ranger XLT utility truck this October. This is in CA but the truck is in the higher weight class so stock emissions equipment are minimal, no cats, no air pump.
Daily driver around town with occasional longer drives on the freeway. Some light towing on occasion. It needs to be able to haul a decent load when asked even though that will be rare.

Smogger 7.9 CR as you all know, dynamic is somewhere in the 6s with the retarded cam. I'd like to aim for high or mid 8s static. Hypothetically, I should be able to do this on a ballpark tune without pinging on 89 octane (dare I say 87) but the real world may say otherwise. I don't want to be overthinking this if stock CR is good enough with a zeroed cam. However, if I fined that she needs to be bored out, a piston swap will be unavoidable.

I know the benefits of zero decking but I'd like to avoid it if I can to help keep cost down and avoid potential hassles of intake fitment. Heads will receive a basic 3 angle and the block will get the basic machine work as needed.

1) What compression ratio have you guys gotten away with on 89 and 87 octane without destroying your timing too much?

2) How many of you are running stock compression with the cam zeroed and how much does it actually help? Good enough for a work truck with light hauling?

2) I'm thinking of swapping the 22cc stock pistons for the EFI 15cc (this gives a higher compression height as well. If I use them with thinner head gaskets then the outer edges of an effective quench can be had (.050~.060), yes / no? What about keeping stock pistons but zero decked? Thoughts or other piston recommendations?

3) I'm okay with keeping the stock cam and new gears set to zero degrees but being that this is a good time to cam swap I might as well entertain the idea. Recommendations for a mild cam on stock springs?

4) I want to remain emissions legal so NOX and HCs are a concern. What emissions numbers have you gotten with your builds?

Carb will be a Holley 600cfm 4160 (Stock carb is trash).

Sorry for the long wind
Thank you in advance ladies and gents for all the help!
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post #2 of 5 (permalink) Old 09-11-2019, 11:30 AM
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I'm building an 87 octane/emissions motor now. Basically a copy of mad porter's 87 tow package you can find on the book of faces. The limits for a 1972 F250 truck are pretty wide and I plan to run EFI and my cam is small at 213/227

Using 12cc dish CP H612 pistons for SCR of 9.25 with 0.002 deck height. These pistons have taller comp height than stock (+0.020) *I believe* and with cut deck my quench is 0.050 (aka just the gasket). So I think stock quench is around 90+, decking gets you ~70. EFI piston w/o cut deck is ~70+ as well, and 70 isn't a good number.

My suggestion is to either
a) leave it stock and address cam timing
b) machine block, raise CR with new pistons, mild cam, port ex side of heads

72 F250
14 F250 6.7, CCLB, 37s
04 Mustang Cobra, 14psi + N20
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post #3 of 5 (permalink) Old 09-11-2019, 01:36 PM
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I built a CA emissions legal +0.030" 460 for my 1985 F-250HD (non-catalyst). With all CA emissions devices intact, it had more horsepower than stock, had more torque than stock, got better fuel economy (14 mpg) than stock, and it passed tailpipe emissions about the same as stock.

In my opinion you need to be willing to make some changes to your engine that you seem to be reluctant to take. Compared to the OEM stock engine, your engine will benefit from the detail work and you will more easily reach your goals with a bit more cam, a bit more compression, decking the block, etc.

I think the 1992-1996 OEM-style piston is a good choice and will put you at about 8.8:1 depending on particulars. I also think you should deck the block to 10.295" and not worry about manifold fitment (that won't be an issue--quit reading regurgitated internet rhetoric). Bowl blend the D3 heads and get a good 3-angle valve job. My 4-speed truck had a 207*/213*@0.050" cam and it was fun to drive in a spirited fashion, but I feel the common shelf 204*/214* would have given better fuel economy and suited the 5th-gear cruise rpm of the ZF 5-Speed (had I gotten around to putting it in). If you have an auto trans then I'd opt for the smaller of those two profiles. As I recall mine ended up going in at 109*...I wasn't too particular and went with a 3-position keyway and used whichever key got me closest to what I wanted. Re-curve your Duraspark distributor. There is more but you get the idea...
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post #4 of 5 (permalink) Old 09-11-2019, 01:46 PM
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HI, Paul Kane and Mad Porter are two of the most knowlageable folks on here..
I'd listen..
good luck

61 Comet W/200
64 International 4dr. truck w/545 stroker
76 Plymouth fury, 76 Olds, 84 Ranger and 56 CJ5
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post #5 of 5 (permalink) Old 09-12-2019, 08:58 PM Thread Starter
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Great feed back, thank you much. I'm taking it all into consideration and I'm feeling more positive about taking things further with the build without crossing CA emission lines; it's my first bb ford build so I wasn't sure how far I could take things.

I'll post back as the build progresses as well as the final results for others that come cross this thread.

If you think of anything else or if any others have advice, it would be appreciated.

thanks again
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