Can pistons be ID'd with heads off?

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DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#1

• Jul 15, 2006

• #1

I have a mildly built, low mile 351w w/o heads. I'm rying to identify the pistons before buying heads so I can determine the CR and correct CC size to order. The previous owner said that they are TRW forged ffycut pistons, but they don't look flycut to me. They have a large oval dish shape in them He also said his CR was 10:1 with 58cc heads. He was running gt40x heads with 1.7 RR and mentioned that they were limiting the power.

So another question would be should I switch to a 1.6 RR ratio to run if I go with 58cc Twisted Wedge heads with the larger valves. The cam is mild, he mentioned actule .554max lift measured with 1.7 RR.

Any input will help.

 

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DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#2

• Jul 15, 2006

• #2

I took a closer look, and do see flycuts within the diashed area.

 

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DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#3

• Jul 15, 2006

• #3

Thanks,

Found this number on the piston top L2466 030 31101 with a symbol that looks like alighting bolt go up within a cirlce.

 

fidstang

New Member

Jul 19, 2005

307

0

0

South Lansing

Jul 15, 2006

#4

• Jul 15, 2006

• #4

Pictures speak a thousand words. As for TRW forged pistons. I know that the stock forged pistons in a 89-92 are TRW's. They have four valve reliefs on each piston. Not sure if any of the 351's from that time line came with them. Post up a pic of them.

 

Hickfied

Member

Nov 9, 2005

413

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16

Morganton, NC

Jul 15, 2006

#5

• Jul 15, 2006

• #5

The lightingbolt makes me thing of SpeedPro....

 

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DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#6

• Jul 15, 2006

• #6

The symbol on the piston is a speed pro symbol:
http://www.campbellenterprises.com/trw_pistons_speed_pro_pistons.htm

I'll e-mail them the part numbers.

 

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DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#7

• Jul 15, 2006

• #7

Hickfied said:

The lightingbolt makes me thing of SpeedPro....

Click to expand...

Here they are at summit:

http://store.summitracing.com/partd...401105+4294908331+4294840125+115&autoview=sku

Now I work on my CR.

 

D

DavidNC

Founding Member

Sep 16, 2002

119

2

16

Jul 15, 2006

#8

• Jul 15, 2006

• #8

The description reads: Recessed head 0.110 in. deep. Approximate compression ratios: 8.56:1 with 69cc, 9.06:1 with 63cc, and 9.30:1 with 60.4cc head.

I know that a gt40x 58cc head was used on it before. Any rearson the larger valve twisted wedge 58cc neads can'tr be used. looks like about 9.5:1 CR. I wanted more, but what kind of power can 9.5:1 support?