317 Heads on 5.3
02-06-2017, 11:04 AM
#1
Teching In
Thread Starter
Join Date: Feb 2017
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
317 Heads on 5.3 So as I've searched the internet it would seem that the 317 heads are best suited for boosted applications when bolted to a 5.3L engine because of their large combustion chamber size. I've also read that some head milling and flat top pistons can help mitigate this. I've also read that the larger valves over the smaller bore of the 5.3 vs. the 6.0 from whence the 317 head came can cause shrouding.
My budget would really like me to make due with what I have, which is this. 5.3L block, 317 heads, truck intake & drive by wire throttle body, power glide transmission (newly rebuilt with stock gear ratios), as of yet undetermined final drive ratio (rear end gear ration, wheel and tire size not yet finalized).
Here is the application. 1940 Chevrolet 1/2 ton pick up. Patina truck not a rat-rod. Should weigh just under 3000# when finished. The goal is for it to sound nasty, be very hard on tires, and a hell of a lot of fun to drive. Not intended for long trips. A few hundred miles in a shot max to an event or whatever.
Machine work is being executed by a reputable local engine machine shop. The heads will be surfaced for flatness which should help boost the CR and we'll go with flat top pistons for the same reason.
Bottom line is this - the universal opinion seems to be not to use the 317 heads on a 5.3 unless you are boosting. Is this gospel truth for those of us who won't be racing and geeking out on every little detail every weekend and constantly upgrading and tweaking things for a few extra HP and to shave a little off of our ET? Is this really going to be a dog? Is the valve shrouding the kiss of death? Assuming this combo isn't the biggest mistake ever, what cam get's me where I want to be? I was kind of leaning toward Comp Cams 54-416-11 until I started to get nervous about the heads. http://www.compcams.com/(S(10nkh0ib3...csid=1087&sb=0
My budget would really like me to make due with what I have, which is this. 5.3L block, 317 heads, truck intake & drive by wire throttle body, power glide transmission (newly rebuilt with stock gear ratios), as of yet undetermined final drive ratio (rear end gear ration, wheel and tire size not yet finalized).
Here is the application. 1940 Chevrolet 1/2 ton pick up. Patina truck not a rat-rod. Should weigh just under 3000# when finished. The goal is for it to sound nasty, be very hard on tires, and a hell of a lot of fun to drive. Not intended for long trips. A few hundred miles in a shot max to an event or whatever.
Machine work is being executed by a reputable local engine machine shop. The heads will be surfaced for flatness which should help boost the CR and we'll go with flat top pistons for the same reason.
Bottom line is this - the universal opinion seems to be not to use the 317 heads on a 5.3 unless you are boosting. Is this gospel truth for those of us who won't be racing and geeking out on every little detail every weekend and constantly upgrading and tweaking things for a few extra HP and to shave a little off of our ET? Is this really going to be a dog? Is the valve shrouding the kiss of death? Assuming this combo isn't the biggest mistake ever, what cam get's me where I want to be? I was kind of leaning toward Comp Cams 54-416-11 until I started to get nervous about the heads. http://www.compcams.com/(S(10nkh0ib3...csid=1087&sb=0
02-06-2017, 01:09 PM
#3
Teching In
Thread Starter
Join Date: Feb 2017
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Conan, I don't have the heads that came with the block. The only heads I have are the 317 casting heads. I understand that ideally the 243/799 castings would be preferable.
How bad will the results be? Horrific? or just less than ideal?
How bad will the results be? Horrific? or just less than ideal?
02-06-2017, 02:18 PM
#5
Teching In
Thread Starter
Join Date: Feb 2017
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Sluggish meaning noticeably poor performance that will have me disappointed every time I drive it or sluggish meaning still fun to drive sounds great but just not as good as it could have been? Should I be considering a different cam?
02-07-2017, 02:02 PM
#6
If this were my project I would be selling the 317's and buying a different set of heads. I would be shooting for 10:1 - 11:1 compression if it were me. You should be able to find a used set of heads for the same price as a new cam.
By sluggish I mean part throttle and low end grunt will be will not be as crisp and fast revving as the engine would be on a full point or more compression.
I under stand saving some $$$ but I'm the type of person that will let my project sit for a little more time to have the final product be everything I was expecting/wanting. Doing the job twice will cost you more in the end.
By sluggish I mean part throttle and low end grunt will be will not be as crisp and fast revving as the engine would be on a full point or more compression.
I under stand saving some $$$ but I'm the type of person that will let my project sit for a little more time to have the final product be everything I was expecting/wanting. Doing the job twice will cost you more in the end.
02-07-2017, 02:06 PM
#7
Teching In
Thread Starter
Join Date: Feb 2017
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Conan,
Thank you. That is exactly the detail I was looking for. I think I'll get the long block finished up and hold off on the heads for a bit. Plenty of other work to do as this is the very beginning of the project. I'll keep my ear to the ground for better heads and pounce when the moment is right.
Thank you. That is exactly the detail I was looking for. I think I'll get the long block finished up and hold off on the heads for a bit. Plenty of other work to do as this is the very beginning of the project. I'll keep my ear to the ground for better heads and pounce when the moment is right.
Trending Topics
02-08-2017, 09:00 PM
#15
I'd say some where between $100-$400 depending on if they have been freshened up or if they are untouched right off an engine. They might be 241's but with a clean up milling they would work nice on a 5.3 with flat tops. I'll call the machine shop I use tomorrow and see what they have and what they want and send you a PM.
03-20-2017, 03:31 PM
#19
I'd have to agree with SANPENGYOU as well. I've got a 5.3 w/ 317s and it's fairly sluggish below 3k but that didn't bother me too much, But if I had a recommendation I'd say find some stock or aftermarket heads JUST MY OPINION tho. Let me know what ya do I'm curious
03-20-2017, 05:50 PM
#20
Teching In
Thread Starter
Join Date: Feb 2017
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Update So I found an LS-1 and 4L60E combo out of a 2001 Camaro with 67k miles that was complete with computer, harness, exhaust, everything. I did some quick calculations and with all of the bits and pieces still needed to make the 5.3 work it was cheaper to go with the complete setup from the Camaro. In addition it will certainly be much simpler for me. And no ugly truck intake as a bonus. So I went ahead and put the Camaro setup into "inventory".