500hp upper end maintenance
#1
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Join Date: Oct 2000
Location: Chesterfield Mo/Loto
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500hp upper end maintenance
I was going to do a valve spring replacement this spring and then started thinking about just swapping out the heads, been doing a lot of reading through the different threads on heads, springs, and cams, I'm not looking to squeeze the last HP or Torque number but would like to see some measurable gain. in performance. I have a couple of questions, 1.) is it possible to swap out the heads and cam with motors in the boat, which is a 42 fountain with side by side motors with a lot of room in front of motors. if so what would be any potential problems if any. I was leaning toward the AFR 305 heads but then started reading about the EQ ch454a heads and since I'm not a closed cooling system it seems the iron head might be a better choice. either way, I go I would buy a bare set of heads and have them assembled question #2 I read about valve guide clearance being an issue what would be a good clearance for guides. When looking at bare heads they all seem to already have the seats ground at multiple different angles what would be the preferred seat widths and do you get to choose when ordering bare heads, and the last question the age-old question cam selection, it seems that the 525efi cam is used a lot because of the 14 LSA is there a part number for that cam from crane. and one last question what lifters came in the 525efi motors I'm assuming they are the GM dog bone style. Thanks in advance
Later
Later
#2
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Crane 168741
except it has 2* less LSA
https://www.jegs.com/i/Crane-Cams/271/168741/10002/-1
BB-3 XTRA 327
Has awesome flow at 0.600 lift. The BP RR does as will with only a 298cc runner, but I’ve seen speculation as to whether that head is produced at all.
You should figure out if you can handle raised exhaust ports, AFRs are .375”
Also get a new intake. About 4-5 episodes ago of engine masters they tested all of them.
except it has 2* less LSA
https://www.jegs.com/i/Crane-Cams/271/168741/10002/-1
BB-3 XTRA 327
Has awesome flow at 0.600 lift. The BP RR does as will with only a 298cc runner, but I’ve seen speculation as to whether that head is produced at all.
You should figure out if you can handle raised exhaust ports, AFRs are .375”
Also get a new intake. About 4-5 episodes ago of engine masters they tested all of them.
Last edited by hogie roll; 04-09-2020 at 11:11 AM.
#4
Charter Member # 55
Charter Member
Doing them in the boat is pain in the azz. I did it once that way and it sucked.
You have carbed 500hp's correct??? I would use the regular Crane 168741 cams with carbed 500's.
You have carbed 500hp's correct??? I would use the regular Crane 168741 cams with carbed 500's.
#6
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I was going to do a valve spring replacement this spring and then started thinking about just swapping out the heads, been doing a lot of reading through the different threads on heads, springs, and cams, I'm not looking to squeeze the last HP or Torque number but would like to see some measurable gain. in performance. I have a couple of questions, 1.) is it possible to swap out the heads and cam with motors in the boat, which is a 42 fountain with side by side motors with a lot of room in front of motors. if so what would be any potential problems if any. I was leaning toward the AFR 305 heads but then started reading about the EQ ch454a heads and since I'm not a closed cooling system it seems the iron head might be a better choice. either way, I go I would buy a bare set of heads and have them assembled question #2 I read about valve guide clearance being an issue what would be a good clearance for guides. When looking at bare heads they all seem to already have the seats ground at multiple different angles what would be the preferred seat widths and do you get to choose when ordering bare heads, and the last question the age-old question cam selection, it seems that the 525efi cam is used a lot because of the 14 LSA is there a part number for that cam from crane. and one last question what lifters came in the 525efi motors I'm assuming they are the GM dog bone style. Thanks in advance
Later
Later