After the math - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Zable49 · 08-01-2013, 10:20 PM

After doing the math and looking up piston #'s. Why would someone build an engine with 7.9 compression and drop it in a truck without running a blower or turbo? Talk about NO power. Guess i should start looking for a set of cheap pistons
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54belair · 08-01-2013, 10:25 PM

85 or 86 octane gas?

Zable49 · 08-02-2013, 12:51 AM

Quote:

Originally Posted by 54belair

85 or 86 octane gas?

Nope This is Washington. 87 - 93

Quote:

Originally Posted by Lattimer

Possibly didn't know what they were doing, or they were building a blower motor and ran out of $$.

Hey maybe I can talk the wife into a blower.

Yeah ok thats not feasable on my budget.

Guess it's new pistons.

Lattimer · 08-01-2013, 11:20 PM

Possibly didn't know what they were doing, or they were building a blower motor and ran out of $$.

mmiddle · 08-02-2013, 12:02 AM

Quote:

Originally Posted by Lattimer

Possibly didn't know what they were doing, or they were building a blower motor and ran out of $$.

2x. Blower motor or stupid.

**WIDESIDE72** · 08-02-2013, 01:21 AM

Are you sure they are aftermarket postons and not stock dished? What is the bore size?
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Zable49 · 08-02-2013, 01:25 AM

Quote:

Originally Posted by WIDESIDE72

Are you sure they are aftermarket postons and not stock dished? What is the bore size?
Posted via Mobile Device

The engine is bored over +60, and the PO said that he bought the engine from a buddy when he threw a rod in the original 350

Zable49 · 08-02-2013, 01:28 AM

I guess the question is, should I pick up flat tops or slightly domed... I will be running stocker heads 76cc due to budget.

Lattimer · 08-02-2013, 07:03 AM

Quote:

Originally Posted by Zable49

I guess the question is, should I pick up flat tops or slightly domed... I will be running stocker heads 76cc due to budget.

Flat tops with 76cc heads winds up around 8 or 8.5:1. Will run well on regular and act like most stock 350's. With .060" over should be a nice running small block.

From there, you can probably get up to 9.5:1 depending on what you buy. Big limit is the stock heads, and you probably won't make a ton more power going any higher.

I'm almost done building a 327, .030" over with 291 double hump 62cc heads. Flat tops are calculating at 9.6:1 compression. I'm gonna have to run premium in it.

**WIDESIDE72** · 08-02-2013, 07:14 AM

I have run flat tops pistons with old 461 double hump heads on 350's and 383's and a thick head gasket on 87 in the past but you cant run a lot if timing. I forget the details as my brother built it for me but it was a daily driver and remember i would add timing and run 91 octane on ocassion and it really woke up! I later switched to 64cc brodix track1 heads and it was alot more detonation proof due to the heads dissipating the heat better.
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**WIDESIDE72** · 08-02-2013, 07:16 AM

I wouldnt run more than a flat top on the street with iron heads uess you want to spring for the extra octane and imo it wont get you much extra power in return.
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08-01-2013, 10:20 PM	#1
Zable49 Registered User Join Date: Jun 2007 Location: Lacey, Wa Posts: 181	After the math After doing the math and looking up piston #'s. Why would someone build an engine with 7.9 compression and drop it in a truck without running a blower or turbo? Talk about NO power. Guess i should start looking for a set of cheap pistons Posted via Mobile Device __________________ 1970 C20 Camper Special SBC350 / TH350 '84 C20 Front Disc Brakes/Control Arms

08-01-2013, 10:25 PM	#2
54belair Registered User Join Date: Mar 2011 Location: bolivar, mo Posts: 839	Re: After the math 85 or 86 octane gas? __________________ 1997 shortie stepside 1968 short stepside 1966 mustang 1966 chevelle ss Dont always go the cheapest route--You can save yourself into the poorhouse! My Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=489030

08-01-2013, 11:20 PM	#4
Lattimer Registered User Join Date: Jan 2013 Location: Mickleton, NJ Posts: 1,776	Re: After the math Possibly didn't know what they were doing, or they were building a blower motor and ran out of $$. __________________ Shawn 1970 Chevy C-10 SWB, 350, TKO 600 5 speed My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881

08-02-2013, 01:21 AM	#6
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: After the math Are you sure they are aftermarket postons and not stock dished? What is the bore size? Posted via Mobile Device

08-02-2013, 01:28 AM	#8
Zable49 Registered User Join Date: Jun 2007 Location: Lacey, Wa Posts: 181	Re: After the math I guess the question is, should I pick up flat tops or slightly domed... I will be running stocker heads 76cc due to budget. __________________ 1970 C20 Camper Special SBC350 / TH350 '84 C20 Front Disc Brakes/Control Arms

08-02-2013, 07:14 AM	#10
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: After the math I have run flat tops pistons with old 461 double hump heads on 350's and 383's and a thick head gasket on 87 in the past but you cant run a lot if timing. I forget the details as my brother built it for me but it was a daily driver and remember i would add timing and run 91 octane on ocassion and it really woke up! I later switched to 64cc brodix track1 heads and it was alot more detonation proof due to the heads dissipating the heat better. Posted via Mobile Device

08-02-2013, 07:16 AM	#11
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: After the math I wouldnt run more than a flat top on the street with iron heads uess you want to spring for the extra octane and imo it wont get you much extra power in return. Posted via Mobile Device



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