Budget 350 From Scratch
Melting Slicks
Joined: Oct 2011
Posts: 3,453
Likes: 67
From: Midland Ontario
NCM Sinkhole Donor
One of the reasons I am hesitant to go for a crate engine is that shipping for me is going to be $1000 from summit! And a crate from my local engine builder is over $4000 before tax.
What are peoples opinions on finding a low mile L31, and simply doing a cam and intake/exhaust swap with no rebuild? Worth it, not worth it? Good idea, stupid idea?
What are peoples opinions on finding a low mile L31, and simply doing a cam and intake/exhaust swap with no rebuild? Worth it, not worth it? Good idea, stupid idea?
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
Yeah Canada is lame when it comes to the import laws/duty/shipping/taxes. My 75 had 17 owners before I bought it (Frankenstein car), and what do you know I had to pay tax on it ($165 on a $1500 car) 
We also have 4 seasons in Southern Ontario, almost winter, mild winter, still winter and construction. Vette friendly I think not!
I am sticking with my budget bolt-ons and will drive it into the ground, then build a nice one when the need arises. I like the idea of the L31 build.
We also have 4 seasons in Southern Ontario, almost winter, mild winter, still winter and construction. Vette friendly I think not!I am sticking with my budget bolt-ons and will drive it into the ground, then build a nice one when the need arises. I like the idea of the L31 build.
Instructor
Joined: May 2012
Posts: 118
Likes: 2
From: CORONA CA
If you go with an old school engine, make sure you break it in properly and use a good zinc based break in oil, 2500 RPM's for 15-30 mintues. Another thing new engine builders will forget to do is prime the oil pump before break-in. Sounds fundamental but it happens all the time.
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
Brian, I will take you up on that offer. It won't be until at least next year though 
I am doing a total rebuild on my 75. New stainless frame, new suspension from VBP, and so on. Had the car for 4 years now, still not a rolling chassis yet! Hope to do lots of work this year. I can't even get insurance until next year. Need to be 25 for classic cars.
GOLF72: I've read about breaking the flat tappet cam so I hope that works out alright. I've heard it is a hit and miss affair.
I am doing a total rebuild on my 75. New stainless frame, new suspension from VBP, and so on. Had the car for 4 years now, still not a rolling chassis yet! Hope to do lots of work this year. I can't even get insurance until next year. Need to be 25 for classic cars.GOLF72: I've read about breaking the flat tappet cam so I hope that works out alright. I've heard it is a hit and miss affair.
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
On a side note, what do you guys think of my parts combo? Edelbrock 2101 Performer intake, Hedman 68280 side exit headers, summit 1103 cam and lifters with the thin Felpro 1094 head gaskets (for the minor compression increase). It is all with stock heads and springs as far as I know, like I said I just don't have the money to put new springs on crappy heads. Nor do I have it to upgrade the heads. I am hoping for it to be just a nice daily driver with that set up, until I can afford the engine build we have been talking about thus far.
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Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
On a side note, what do you guys think of my parts combo? Edelbrock 2101 Performer intake, Hedman 68280 side exit headers, summit 1103 cam and lifters with the thin Felpro 1094 head gaskets (for the minor compression increase). It is all with stock heads and springs as far as I know, like I said I just don't have the money to put new springs on crappy heads. Nor do I have it to upgrade the heads. I am hoping for it to be just a nice daily driver with that set up, until I can afford the engine build we have been talking about thus far.
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
Couple questions then,
A: Will I be wreaking anything by using the stock springs or will it just not use the cam to its potential? (I've heard the stock springs are on the light side?)
B: I have looked around and can't find out any info on how to match springs to any given cam.
C: If I get a set of heads for my L48 will they bolt onto the L31 or would I need to stick with the older style block inorder to reuse the heads?
D: Any recomendations on "good" heads? There seems to be so much choice I find it a little overwhelming. Any experience/knowledge is greatly appreciated!
I apolgise for the novice questions. (If some of this should be broken out into a different thread let me know)
Dave.
A: Will I be wreaking anything by using the stock springs or will it just not use the cam to its potential? (I've heard the stock springs are on the light side?)
B: I have looked around and can't find out any info on how to match springs to any given cam.
C: If I get a set of heads for my L48 will they bolt onto the L31 or would I need to stick with the older style block inorder to reuse the heads?
D: Any recomendations on "good" heads? There seems to be so much choice I find it a little overwhelming. Any experience/knowledge is greatly appreciated!
I apolgise for the novice questions. (If some of this should be broken out into a different thread let me know)
Dave.
Last edited by Vettefied; May 11, 2012 at 09:49 AM.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Couple questions then,
A: Will I be wreaking anything by using the stock springs or will it just not use the cam to its potential? (I've heard the stock springs are on the light side?)
B: I have looked around and can't find out any info on how to match springs to any given cam.
C: If I get a set of heads for my L48 will they bolt onto the L31 or would I need to stick with the older style block inorder to reuse the heads?
D: Any recomendations on "good" heads? There seems to be so much choice I find it a little overwhelming. Any experience/knowledge is greatly appreciated!
I apolgise for the novice questions. (If some of this should be broken out into a different thread let me know)
Dave.
A: Will I be wreaking anything by using the stock springs or will it just not use the cam to its potential? (I've heard the stock springs are on the light side?)
B: I have looked around and can't find out any info on how to match springs to any given cam.
C: If I get a set of heads for my L48 will they bolt onto the L31 or would I need to stick with the older style block inorder to reuse the heads?
D: Any recomendations on "good" heads? There seems to be so much choice I find it a little overwhelming. Any experience/knowledge is greatly appreciated!
I apolgise for the novice questions. (If some of this should be broken out into a different thread let me know)
Dave.
Keep the shiny side up!
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
http://www.kmjent.com/cart/product.php?productid=735
And you can find 2101 intakes on ebay for 50-75 bucks, you're taking a small risk any time you buy something used off ebay, though. Just something to think about.
Keep the shiny side up!
Scott
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
[edited for something dumb I said without thinking 
]
Valvesprings ensures the valves close. Weak springs fail to hold the springs at higher RPM; stock, old, weak springs can go into "float" as low as 3500-4000 RPM. Especially with an aftermarket cam, it's critical to ensure the springs are matched - most cams will come with specific recommendations for seat and open pressures.
Springs that fit stock heads and valves - ~1.25 OD, 1.700 installed height and more than the stock 80# springs...usually 100-110# - are "Z/28" springs, available from a million places
Any GEN I head will bolt to any GEN I block.
"Good" heads are a function of budget - many, many choices but ultimately driven by how much you have to spend...which determined how much power you can make.
]Valvesprings ensures the valves close. Weak springs fail to hold the springs at higher RPM; stock, old, weak springs can go into "float" as low as 3500-4000 RPM. Especially with an aftermarket cam, it's critical to ensure the springs are matched - most cams will come with specific recommendations for seat and open pressures.
Springs that fit stock heads and valves - ~1.25 OD, 1.700 installed height and more than the stock 80# springs...usually 100-110# - are "Z/28" springs, available from a million places
Any GEN I head will bolt to any GEN I block.
"Good" heads are a function of budget - many, many choices but ultimately driven by how much you have to spend...which determined how much power you can make.
Last edited by billla; May 11, 2012 at 03:37 PM.
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
What about this kit from Summit http://www.summitracing.com/parts/SUM-174001/, is that sufficient for the Sum1103 cam? What if the cam does not have recomended spring pressures? Is there some sort of rule of thumb or eguation to determine the correct springs?
If it fits on the L31 block then I would be willing to spend a little more so I can reuse them on another short block down the road. For example I was looking at the Dart SHP or maybe TFS 23*. Like I said a little overwhelming in that area. Is there anything better anyone can suggest. I would rather spend the extra couple hundred on good heads and keep reusing them, assuming it is a worthwhile increase in quality/performance.
Scott: The parts I listed in my combo I already have purchased. If that spring kit from summit will work well on my L48 heads, I can "spring" for those...ok bad joke...
If it fits on the L31 block then I would be willing to spend a little more so I can reuse them on another short block down the road. For example I was looking at the Dart SHP or maybe TFS 23*. Like I said a little overwhelming in that area. Is there anything better anyone can suggest. I would rather spend the extra couple hundred on good heads and keep reusing them, assuming it is a worthwhile increase in quality/performance.
Scott: The parts I listed in my combo I already have purchased. If that spring kit from summit will work well on my L48 heads, I can "spring" for those...ok bad joke...
Racer
Joined: Apr 2012
Posts: 464
Likes: 1
From: Austell Georgia
Can I ask why not a 383? If you're building your own block anyway the clearancing is not difficult at all. It will give you everything you're looking for at a reasonable price. When you have money to spend you will get more return with a good set of heads than anywhere else. Remember...buying great parts no matter what the cost will be worthless unless they are matched to work together!
Instructor
Joined: May 2012
Posts: 118
Likes: 2
From: CORONA CA
Excellent point. In this build, the engine is a 355 with 10.5:1 compression, NOT STROKED, with .202 Aluminum heads. Everything was matched with the lumpy cam. The engine was going into my Camaro but I stuck in the Porshe instead. Keep in mind with this build, the weak link is the Porsche 901 transaxle which can take a max of 450 hp so I need to stay below that which I accomplished.
Thread Starter
Intermediate
Joined: May 2012
Posts: 33
Likes: 0
From: Ontario
I was only concerned with going the 383 route if I had an existing short block. I didn't want the expense of switching over. But if I do my own block then yes I would definitely go with a 383.
I am considering going with a used L31 and bolting on cam and heads. In which case I would again only go with the 350....Lot to think about
I am considering going with a used L31 and bolting on cam and heads. In which case I would again only go with the 350....Lot to think about
Instructor
Joined: Feb 2012
Posts: 145
Likes: 2
From: hudson valley ny
I was only concerned with going the 383 route if I had an existing short block. I didn't want the expense of switching over. But if I do my own block then yes I would definitely go with a 383.
I am considering going with a used L31 and bolting on cam and heads. In which case I would again only go with the 350....Lot to think about
I am considering going with a used L31 and bolting on cam and heads. In which case I would again only go with the 350....Lot to think about