390 FE compression/piston build question
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390 FE compression/piston build question
I have a 72 390 FE truck motor that I would like to change the compression of. I believe the compression is 8.2.1 for these stock motors. Hopefully after I'm done rebuilding it, I could have it in the 9.5.1 area. I'll be keeping the D2TEAA heads. I want to change over to a 1.760 car piston but I'm unsure of what to buy. Advice on pistons?
I don't want to bog the motor. Just want it to be a nice Sunday cruiser is all and something to rip around with.
List of parts for the motor
Intake
http://www.summitracing.com/parts/ed...view/make/ford
Cam which I order the whole kit from lunati
http://www.summitracing.com/parts/lun-10330453lk
Carb which I already had
http://www.summitracing.com/parts/hly-0-80783c
Doug's headers
I don't want to bog the motor. Just want it to be a nice Sunday cruiser is all and something to rip around with.
List of parts for the motor
Intake
http://www.summitracing.com/parts/ed...view/make/ford
Cam which I order the whole kit from lunati
http://www.summitracing.com/parts/lun-10330453lk
Carb which I already had
http://www.summitracing.com/parts/hly-0-80783c
Doug's headers
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The 1.76 car piston was installed as a flat top for the 10.5 motors or with a slight dish for the "Regular Fuel" 9.5 motors in the '66 and up 390s.
This piston is also used, flat and dished, in the 360 on top of the 352 rod and crank.
I would cc the heads and figure out dish or flat for compression. Head volume varies a bit in production, so best to do the math before choosing the pistons.
This piston is also used, flat and dished, in the 360 on top of the 352 rod and crank.
I would cc the heads and figure out dish or flat for compression. Head volume varies a bit in production, so best to do the math before choosing the pistons.
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Posts: 34,481
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Production variations can make those up to 74 cc, thus the suggestion to cc them.
You will need valve springs with that cam, that's one thing.
I would call Lunati. That cam may support a little higher compression.
Have you checked your bores yet?
This one gets you into the low 9s with a .040 head gasket:
https://www.uempistons.com/index.php...cd59d18db9844d
You will need valve springs with that cam, that's one thing.
I would call Lunati. That cam may support a little higher compression.
Have you checked your bores yet?
This one gets you into the low 9s with a .040 head gasket:
https://www.uempistons.com/index.php...cd59d18db9844d
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Already payed the full $460 for springs, cam, lifters, timing, etc. My block is the stock 4.050 bore. I've been doing some number crunching and Im curious if I could run 4v pistons to boost the compression? This would make it around 9.75.1.
Speed-Pro Forged Pistons L2291F - Free Shipping on Orders Over $99 at Summit Racing
Speed-Pro Forged Pistons L2291F - Free Shipping on Orders Over $99 at Summit Racing
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From: Stanley, VA
For a street engine I prefer cast pistons. I used Silv-o-lite 1131 pistons on my rebuild, flat tops w/ four valve reliefs and a 1.760" compression height.
They're available from Summit and you can get either cast or hypereutectic (1131H). Like I said I prefer cast for the street, I don't like the bigger ring end gaps needed to run the hypereutectic pistons either.
Set of eight (std. size) from Summit $159.97
http://www.summitracing.com/parts/uem-1131-std
NOTE: In the specs, Summit says the wrist pins are press fit, that's incorrect. The 1131's are floating pins like stock. It also shows them as being hyperutectic, again, they're not. These are the cast versions.
They're available from Summit and you can get either cast or hypereutectic (1131H). Like I said I prefer cast for the street, I don't like the bigger ring end gaps needed to run the hypereutectic pistons either.
Set of eight (std. size) from Summit $159.97
http://www.summitracing.com/parts/uem-1131-std
NOTE: In the specs, Summit says the wrist pins are press fit, that's incorrect. The 1131's are floating pins like stock. It also shows them as being hyperutectic, again, they're not. These are the cast versions.
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For a street engine I prefer cast pistons. I used Silv-o-lite 1131 pistons on my rebuild, flat tops w/ four valve reliefs and a 1.760" compression height.
They're available from Summit and you can get either cast or hypereutectic (1131H). Like I said I prefer cast for the street, I don't like the bigger ring end gaps needed to run the hypereutectic pistons either.
Set of eight (std. size) from Summit $159.97
http://www.summitracing.com/parts/uem-1131-std
NOTE: In the specs, Summit says the wrist pins are press fit, that's incorrect. The 1131's are floating pins like stock. It also shows them as being hyperutectic, again, they're not. These are the cast versions.
They're available from Summit and you can get either cast or hypereutectic (1131H). Like I said I prefer cast for the street, I don't like the bigger ring end gaps needed to run the hypereutectic pistons either.
Set of eight (std. size) from Summit $159.97
http://www.summitracing.com/parts/uem-1131-std
NOTE: In the specs, Summit says the wrist pins are press fit, that's incorrect. The 1131's are floating pins like stock. It also shows them as being hyperutectic, again, they're not. These are the cast versions.
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