GT40P Head Replacement |
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FFImarine
Senior Member Joined: June-21-2016 Location: Medina Status: Offline Points: 145 |
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keno..... ARP does state you can reuse there head bolts if you use there moly lube and torque them to there spec but they can only do that one time after initial use. Your more then welcome to reuse head bolts as many times as you like (it’s not my engine) but is $80 really worth it??? I think not
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3750 |
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I called on engine rebuilders that built a combined 8-10,000 engines per month.
On engines that did not use TTY bolts they always re used the head bolts, main bolts, connecting rod bolts. These engines all went out the door with warranty. I do know my performance accounts always recommended new rod bolts on the small block GM 350 engines. Again, these were for performance builds because they have seen so many fail on high RPM engines if not replaced. Other engines they re use every part that has proved to be reliable. One final note for discussion. Many head bolts are built in the far EAST today, not New York but overseas. Do you trust the made in America bolts your engine had from the factory or the copies made in China. Other than ARP you will be searching hard to find made in America today. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11118 |
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Good thinking Zach I'm gonna change my studs too, 'cause I don't want to worry about my nuts falling off |
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2979 |
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Brian:
What will you be using for rockers on the new heads? |
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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I was hoping that I could reuse the existing ones, but am open to any ideas! I went with the GT40P's based on Keno's recommendation and am ready to listen to all advice on this project.
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Mille1sj
Senior Member Joined: October-01-2007 Location: United States Status: Offline Points: 278 |
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I used 1.6 Roller rockers for the GT40P heads I put on our 302. I believe they are the Ford Performance rockers.
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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You can reuse your rockers and pushrods but you should check your lifter preload. Later on if you wish you could go for roller rockers
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11118 |
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Make sure you get a recommendation from someone who's done it (The 1.6 roller rockers) on a GT40 with it's "pretty finicky" ECM. Numerous people have swapped from GT40 to 40P heads without a problem, some have put a new cam in that wasn't much different without a problem, but once you're very far from original you seem to come up with the loping idle issue that's hard to solve. The 1.6 rockers are pretty much like putting a new cam in and might just be too much for the ECM Edit............this should say using 1.7 roller rockers not 1.6 since the stock ratio is 1.6 (thanks TRB) For that reason, I'd use the original pushrods and rockers and not throw anything else into the equation that might make the ECM have trouble controlling the engine as smoothly as it did before. I've done the head swap only with no running issues. |
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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Although some of you claim to be 'backyard hacks' , I can't thank you enough for all your inputs....I might have learned more on this forum than i did after 6 years of 'struggling ' to get through school...Admittedly, I had flashbacks after the 'simple stress-strain' comment Appreciate everyone's help. I know 'swapping' out these heads is probably a simple task for many of you (and I"m no pro) so it is a little more of a challenge to this ol' bus driver. Looking to make sure i've got all the i's dotted and t's crossed! Thanks again....
A little more background....I'm told this boat had some 'issues' before I bought it with the ECM and it was replaced...seems to be running well with the new or used replacement with the exception of the water leaks .and a few 'noises' that i wouldn't have honed in on. Without all of the time I've spent trying to work out all the gremlins I probably wouldn't have heard most of 'em with the music cranked up! |
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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OBTW- I work with a guy that is selling an 'older' Malibu if you know anyone in the market...I'll get the flyer and post if there is an interest.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21186 |
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There’s nothing that stock ratio (1.6) roller rockers would impact... theyre just a little lighter weight and less friction. Increased ratio on the other hand, would be a change similar to cam that may cause tuning issues.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11118 |
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For some reason I had 1.7 roller rockers on the brain when I wrote the earlier post about staying with the stock rockers Edited the previous post |
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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Gents, I was able to pull one of the head bolts and confirm that it fits! Glad you pointed it out so it will be one less thing that could potentially hold me up once we start pulling it apart... |
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13515 |
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Potentially undersized bolt holes on the new heads won’t hold you up pulling it apart
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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Here's a pic of the flyer that was posted @ work! Hope it's not a forum party foul to 'advertise' for him since it is not a Nautique:) |
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BRKOUT1K
Groupie Joined: December-25-2019 Location: Texas Status: Offline Points: 40 |
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Well I finally was able to get the heads installed. So far we ran the motor on the hose yesterday and at the ramp this morning. The motor sounds good to my untrained ear...We are almost ready to hit the lake with the kids after some good weather and a couple of maintenance runs Hollywood, you were correct and your eyeball calibration was spot on!. Despite 2 of the holes not being drilled out for the 1/2 bolts, it didn’t hold us up from pulling it apart. Unfortunately we discovered the issue during the installation and obviously held us up for a few days. Just wanted to drop a quick note to thank everyone for their inputs & assistance on the project. Thx Brian |
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aupatking
Senior Member Joined: October-03-2013 Location: Alabama Status: Offline Points: 139 |
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I’m sure one of you guys knows: what’s the spec torque lbs and sequence for the GT40 heads on the 351W?
My current project is ready to have it's engine put back together. It had a rebuild with 10-12 hours on it. Not sure if the head bolts weren’t torqued or were just stretched enough to not hold torque, but those cylinders were slam full of antifreeze when I pulled it apart and the impact didn’t even stutter pulling the head bolts. On the bright side, rebuilding a 12 hour engine is the cleanest rebuild I’ve done. |
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02 SN 196 TSC2 ZO
01 SN 196 TSC1 98 SN 196 TSC1 97 SN 196 TSC1 93 SN 196 NWZ |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3750 |
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For 351W 1973-1998 Fel-Pro says to torque in 3 steps.
1. torque all Head bolts to 85 ft pounds 2. 95 ft pounds 3. final torque to 105-112 foot pounds for 1/2" bolts I will look for a picture of the torque sequence for this head. |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3750 |
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351W Torque Sequence
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