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Discussion Starter #1 (Edited)
Looking for some info on converting a Gen IV block to roller it started life in motorhome and I'm keeping it std bore with LS6 piston rods and crank and I also picked up a set of lifters - (came with pistons) they are Speed Pro's so why not? I'm looking for a cam similar to LS6 that's a hyd roller compression will be 10-10.25:1 with open chamber aluminum heads and be pump gas compliant
and also whats needed with cam - a stepped face and a plate to limit movement like a late SBC roller or a button or? I have converted few small blocks that were roller ready easy to do but this is my first BBC that will be roller thanks ahead for the advice guys

FWIW I'd love a set of snowflake alum heads but some of them are very high priced, so whats a good square port bare head that doesnt have huge intake volumes for this mid size BB? square port only because I have a 163 intake (going for original look)
 

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For the markIV engines I use just a thrust button on the front of the cam. We are doing a stock appearing 454(496) in my buddies 74 Corvette. looking at the Crower 01403, or the Comp 11-420-8 for his car. He is going to run the stock 781 heads and low rise manifold. I was doing a stock appearing L88 engine setup for my Camaro, but changed my mind and am dropping in the old 565 with Brodix BB3 xtra 327cc heads.
 

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Try Straub Technologies and look at a top end kit. Having all components planned together will give you the best end result. A HR along with as cast AFR heads will create a great pump gas combo.

A custom cam is not your lowest cost option but you get what you pay for.
 

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Try Straub Technologies and look at a top end kit. Having all components planned together will give you the best end result. A HR along with as cast AFR heads will create a great pump gas combo.

A custom cam is not your lowest cost option but you get what you pay for.
I did the complete Straub package and i'm very happy with it and it was NOT cheap in any way. Full roller package, morell lifters, harland sharp rockers, everything. However, with that being said, if I had to do it all over again, i'd probably go with a complete Bullet Cam package.
This is my Straub specs for my 454;
Adv. 288/300
.050" 229/241
LIft 600/570 with 1.7
109 Lobe Sep
 

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As a former engine builder I can tell you that pistons are a consumable. You can put used pistons back in the same hole that they came out of with new rings as a an economy move, but you are going to loose compression as the cylinders will not seal as well as a fresh bore (with a block plate) and honed to fit fresh pistons. Taking pistons out of one engine and sticking them in another will lead to a rebuild sooner than you expected.

Mark IV (two piece rear main seal) blocks require roller tappets with a tie bar. Big blocks like lift, lots and lots of lift. Unfortunately such cams are very hard on the valve train and result in broken valve springs unless you check the valve springs for loss of spring tension (you can check the spring tension on the heads with a tool referenced below).

A 454 is close, but not close enough to use rectangular port heads on the street. You need around 500 cubes to utilize the flow capacity of 320 cc rectangular port heads, otherwise they will be lazy at low RPM as the port velocity allows the gas to fall out of the air flow. This is why the engineers at Chevrolet specified Edelbrock Performer RPM-O 280 cc heads with bigger valves for the ZZ502 street engine with a hydraulic roller , but used Edelbrock Performer RPM-R heads 320 cc rectangular port on the HO 454 with a solid roller that was designed to rev to 8K. Rectangular ports requires bigger displacement engine for idle to 4,200 RPM operation; or to twist the engine higher than you will ever encounter on the street for a 427 to 454 engine.

As to cams in general: Lift is useful every where in the RPM band and allows the engine to breath better. As I mentioned higher lift requires reinforcing the valve train (roller rockers with a stud girdle or shaft mount rockers, double or triple wound springs to dampen valve spring harmonics and control the mass of the valves, larger diameter push rods with matching push rod guide plates),

Duration is increased from the stock 182 degree to 196 degree range to larger numbers to hold the valves off the seats for a longer period of time. This is necessary to give air a chance to get into the cylinder as RPM increases. A longer duration cam gives you that rumpity-rump sound you hear on a race car that launches off the line at wide open throttle. That rumpity-rump sound is the sound of lost power. You are sacrificing bottom end torque that gets your car rolling off a stop light for HIGH RPM operation. If you are not racing you don't need that noise other than to feed your ego. Just don't be surprised if a Jap turbo car kicks sand in your grill.

Finally the issue of Lobe Separation Angle also affects that rumpity-rump sound. The bigger the number (the wider the lobes are separated the less noise, and the more power you will have for the street. That noise is air being pushed back into the intake manifold causing your carb to dump in more gas than needed; which causes the motor to load up. So a wider LSA with the same lift and duration as found on EFI computer controlled cars will run just as well on the street, but it reduces overlap (that rumpity-rump sound).

If you are buying an off the shelf cam my advise is to stay off the bottom of the page. Also consider truck pulling cams and Jet boat cams to get the numbers (lift duration and LSA) that you want in an off the shelf cam. I used to use custom ground solid roller cams in all of my cars (originally bought them from Harvey Crane back in the seventies, but changed brands over to Comp Cams in the eighties, then over to Lunati after the turn of the century as the quality at Comp of their roller tappets fell off ).


Big Dave
 

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Discussion Starter #7 (Edited)
Dave please do not post in my thread with all your unrelated suggestions. you are the reason I left novas.net I had specific questions that you ignored instead you try to come off as some swami to the car world wasting your time and mine please do not post in my thread anymore
Mods Do not delete my post again I'm being polite
 

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I would second Straub for a cam. I would also go Gen V on the cam and use a retainer. Works great.
 

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Lsa... Narrow will make more power, it's been done time and time again, but at the expense of idle quality.
There is ALWAYS a compromise with a cam.
I had a 250/256 on a 108 in my 489 and it was alright on the street with a high stall. Went to a stick and it was kind of wheezy.
Changing to a Straub cam myself it's on a 109
 

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Zman,
Is very easy to use a late model Gen5-6 cam in any big block. 99% of them are already drilled for the cam retaining plate. You will need the correct timing set but thats not an issue. You will also need link bar lifters as you know. It makes absolutely no sense to use a old style cam with a cam button. The retaining plate setup is bulletproof and every cam manufacturer I know of offers all of their grinds on the new style core.

As far as picking a camshaft, find a manufacturer that you feel comfortable with and tell them as many details as you can about your combination. The let them tell you what cam you should use.

If you have any questions on the retaining plate setup feel free to ask here or PM me.
 

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This ^^^^^^^^
 

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Zman,
Is very easy to use a late model Gen5-6 cam in any big block. 99% of them are already drilled for the cam retaining plate. You will need the correct timing set but thats not an issue. You will also need link bar lifters as you know. It makes absolutely no sense to use a old style cam with a cam button. The retaining plate setup is bulletproof and every cam manufacturer I know of offers all of their grinds on the new style core.

As far as picking a camshaft, find a manufacturer that you feel comfortable with and tell them as many details as you can about your combination. The let them tell you what cam you should use.

If you have any questions on the retaining plate setup feel free to ask here or PM me.
This. Just don't use the summit retaining plate... My holes were slightly too wide. I fixed it but it was somewhat annoying to do when you have everything ready to assemble and that's what you over look.
 

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Discussion Starter #13
Zman,
Is very easy to use a late model Gen5-6 cam in any big block. 99% of them are already drilled for the cam retaining plate. You will need the correct timing set but thats not an issue. You will also need link bar lifters as you know. It makes absolutely no sense to use a old style cam with a cam button. The retaining plate setup is bulletproof and every cam manufacturer I know of offers all of their grinds on the new style core.

As far as picking a camshaft, find a manufacturer that you feel comfortable with and tell them as many details as you can about your combination. The let them tell you what cam you should use.

If you have any questions on the retaining plate setup feel free to ask here or PM me.
Thanks kind of figured that would be like when you convert a SBC plate bolts and special timing set I did find a guy selling a Lunati Bare bones? cam with this spec
Retro-Fit Hydraulic Roller. Fair idle, great low to mid range power for daily usage. ;Advertised Duration (Int/Exh): 276/286 ;Duration @ .050 (Int/Exh): 218/228 ;Gross Valve Lift (Int/Exh): .570/.570 ;LSA/ICL: 112/108 ;Valve Lash (Int/Exh): Hyd/Hyd ;RPM Range: 1600-5600
for a fair price and I have to say I am no cam guru but its not from the bottom of the cam page - what do Y'all think?
 

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You will need to narrow down the head selection first.
 

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Thanks kind of figured that would be like when you convert a SBC plate bolts and special timing set I did find a guy selling a Lunati Bare bones? cam with this spec
Retro-Fit Hydraulic Roller. Fair idle, great low to mid range power for daily usage. ;Advertised Duration (Int/Exh): 276/286 ;Duration @ .050 (Int/Exh): 218/228 ;Gross Valve Lift (Int/Exh): .570/.570 ;LSA/ICL: 112/108 ;Valve Lash (Int/Exh): Hyd/Hyd ;RPM Range: 1600-5600
for a fair price and I have to say I am no cam guru but its not from the bottom of the cam page - what do Y'all think?
As said, narrow down you head selection. Will it run pretty well? Yes. Will it be optimized to make the most power? No.
 

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Discussion Starter #16
Aluminum to save weight square port open chamber looking for 300-320 intake ports is what I'm thinking
 

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Discussion Starter #18
Just a street motor for polluting and shortening tire life old school style
 

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Just a street motor for polluting and shortening tire life old school style
Sounds like a great plan. I love the day two/Baldwin Motion look and sound. The only reason I went away from that myself is the car has too many changes I would have to set back to original-ish. You know, too far down the rabbit hole. As said, you will not be making the maximum power you could, but that is not the intent. Cylinder heads is the biggest power gain you can make over the old school heads. Better flowing heads with less cam will make the same power and be more drive-able. It doesn't give the same look under the hood unless you spend a lot of time disguising the cylinder heads. I figured my L88 496 was going to be down by at least 100 hp over a new style cylinder head. I have a bunch of BB parts that can be had for shipping cost, and a bunch left over from my 496. If you are interested PM me.
272809
 
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