Engine Heads and Cam Swap. Am I doing it right so far?

ClevelandTim

Member
Jan 14, 2018
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Cleveland, OH
Guys,
I have an F4TE 351W roller block. I'm upgrading to a hyd. roller cam and TFS TW 170 heads (58cc).
1) I measured pushrod length for the new cam and came out to 8.05. I can't find out any info on the dish on the hyperutectic piston, but it's pretty cavernous, like maybe -20? I included a pic of the valve spring head with the marker swipe across the center like I've read and watched videos on for determining pushrod length. Does that look good?

2) For the hell of it I clay tested the GT40 heads with 1.7 rockers, .and old standard cam and lifters 491/510 , on the yellow clay and it squished the clay but was well within a safe margin.

3) Next I clay checked the TFS TW's with my new cam (XE274HR) on the green clay. It didn't even leave a mark. Is this because of the improved valve orientation on the TFS heads? I thought with a .555/.565 lift and bigger valves it would at least touch the clay. The cam is installed straight up. I made two solid roller lifters for the test.

Big question is - Do I have a ton of room for PVC or am I doing something wrong? I've done head swaps before but never swapped from standard to roller cam and obviously don't want to have a bad experience when I hit the key. Any thought?

Thanks in advance,
Tim

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90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
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You need to also check piston deck height. With the piston at TDC how far does it sit in or out of the cylinder ?

You need to lump the clay up until you get a valve imprint. The valves obviously look nowhere near touching the piston.

Roller pattern on the valves look ok.

Hope someone chimes in with a way to check cylinder cc to calculate your compression ratio.
 

nickyb

WAIT,you now have a pair?
10 Year Member
Apr 3, 2009
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Go get a syringe 20cc's. Or bigger.Fill it with light oil and make sure block/ piston is level.,slowly fill dish in piston till full.minus what's left in syringe from total and bam!
 
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