The Jalopy Journal
Discussion in 'Traditional Hot Rods' started by bfalfa55, Jul 23, 2013.
I have my 265 back on the stand. It's getting re cammed and kinda detuned for the street.
Cool Roothawg. Can you shed any light on the pics I took of the heads ?
What are you going to run for a cam in yours ? I found out the marking on the heads is from the company I bought them from for ID purposes. I think for my purposes, the L98 heads massaged a bit will be a good fit. Do you have an idea of how much can be milled off these heads to increase compression ?
I think I have come to choose the Comp Cams Xtreme 4 x 4 roller cam as my choice for my build. It is .474 lift, Dur @ .050 230 Intake, 234 Exhaust, 111 LSA. I have also thought about retrofitting the LT4 Hot Cam, but the Xtreme cam seems to yield some better numbers.
Gm uses that stamp on some current pre production stuff we get for LS engines.
I dunno yet. I talked to Howards about a hyd roller. We will see.
I dunno about the stamp. It's cool though.
My problem is finding an overdrive manual transmission for mine. I have a flywheel, but the WC T-5's are like hens teeth.
If I win the lotto I am buying one of these.
I think I have come to choose the Comp Cams Xtreme 4 x 4 roller cam as my choice for my build. It is .474 lift, Dur @ .050 230 Intake, 234 Exhaust, 111 LSA. I have also thought about retrofitting the LT4 Hot Cam, but the Xtreme cam seems to yield some better numbers. What do you think about one of these with some ported L98 heads ?
Is the Comp Cams a Hyd Roller or solid? If it is a solid I wouldn't run it on the street. Here's what is in the Fly. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=307&sb=2
No it is a Hyd. roller.
Hey Roothawg, how accurate do you feel Comp Cams CamQuest is ?
I dunno. I have never tried it. I always fill out the sheet and wait on an email response. I am torn, I have the cam that was in the 265 back in 1958. It was an Engle 95 solid cam. I ran it in my 283 in high school. It's tame by todays standards. It does have a good sound though. snappy response too.
Well, the cam you listed is in their list on CamQuest. Try entering it and all the other engine info and see if you think it is accurate to how the Fly performs. It would be interesting to know since you have actually run the cam in an engine and on the track.
I like the cam. But, I have an 8" converter behind it and it's a mechanical roller. For a track car it's great, but for the street it would be too much. The best time with the 265 was 12.01 at 119 mph, running a glide and a 5.13 ring and pinion, 462 2.02 heads, hilborn injection, and an ultra rev kit. Slow by todays standards, but it is a period correct motor.
It is still impressive and sounds like fun to me. I would like to see a video of it running. Do you have any ? That would be cool to watch.
. Not a good run, but the only video we have.
That was really cool ! It looks like it can be a handful sometimes !
It's always interesting to say the least.
What do you guys think some good flow numbers would be to get out of these L98 heads ? Stock they say 196 cfm @ .500. I know I don't want to go crazy on them porting because it isn't necessary for the smaller cubes. Plan was to smooth them up and fix the imperfections. How far do you think I should go ?
I'd focus on the short side radius, gasket match and the usual guide area and clean up under the valves where the machining notches are in the flow path. If it hasn't had it done before.
Also leave the intake rough, don't smooth or polish it. Kills torque. Not what we thought 35-40 years ago. lol
Thanks for the advice. I do have some uneven casting areas in the intake runners. Do you suggest just using a burr to blend them or use a sanding cone and leave it rough that way ? I never fully polish my runners but have cleaned them of all the casting but left a bit of roughness with a coarse grit sanding cone. What method do you use or suggest ?
FINALLY, a positive update in a forward direction ! My oldest daughter is now married, so I can spend some money !
I did a full cc job of my dome pistons in the bore. I will be right in the 10.5:1 compression ration depending on what head gasket I use. I have to use 350 style due to the mods the previous owner did to the top of the bores. So, my question is: what is the thinnest 4.03 bore diameter gasket I can use that will work with my L98 aluminum heads ? If I use a shim style gasket I will be around 10.68:1 if I use a .028 thick gasket I will be around 10.48:1.
I don't care if the gasket is pricey, as long as it won't cause me issues with the aluminum heads.
I also must add, piston is .015 down the bore, so I can't go too thin.
I am thinking these gaskets will work well, I just have to get them and make sure they are a match with the areas the original engine owner modified on the top of the cylinder bores. He scalloped areas to match the head gaskets he was going to use. Not the best thing for a little engine like this but they only take away 2cc's away from my compression but that isn't going to hurt me because I will be at 10.5:1 even with them. I am trying to see if I can just get them from a Chevy dealership parts counter in case they aren't compatible.
If your calculations indicate you can use a .028 gasket I would contact a gasket company like Cometic and get them to make you some gaskets with proper bore size. I doubt those GM gaskets come in any smaller than 4.100 in actual bore size.
Your son has good taste in the tri-5 chevies. My favorite is the '56 2-dr post, Bel-Air to 150. Doesn't matter. Baddest sedan of the three years. I have a clean 283 out of a '65 Bel-Air with a number showing it was built in '58 to '62 with powerpack heads. Go figure. Good luck with your build. Gary
Thanks Dblgun. I am considering that, Cometic is basically in my backyard. Here is a review on the gasket I listed above:
Originally for new factory engines. Strictly 4.0" bore, no oversize possible without burning fire ring. GM makes a 4.100" for that. Great for head re & re on stock engines but perfect on small bore 265, 283, 305, 307 when using heads from 327, 350, or 400. Putting L98's on a 305? This works by staying out of the combustion chamber.
What you said is exactly why I would like to buy them locally so I can check first before I get into the pricey gaskets if I don't have to.
Thanks but he has no choice according to his Grampa ! He won't be finding one soon, he is saving up his money. The build shold be fun, I think it is going to run better than what some people think with a very modern cam.
bfalfa55, if that is the case then it would be a pretty nice little gasket for the price. I think you're on the right track getting a look at the gasket local in the event it is not what you're looking for. 3-5 cc's in a bore that small has an impact on CR real quick. I just recently put together a 283 and it is getting very difficult to find parts and pieces for SBC's with anything short of a 4" bore. Brodix was the only aftermarket company that would even consider doing a set of head castings for me and both head gaskets and piston rings were custom orders. All this to build a 288" engine that at one time was the staple of the hot rod world.
This is the cam I was looking at and ironically it is the exact cam Lunati suggested when I talked to them. Not purchased yet, ordering my gaskets so I can get to porting my heads.
Voodoo Retro-Fit Hydraulic Roller Cam & Lifter Kit - Chevrolet Small Block 270/278
Lunati’s Voodoo series of camshafts deliver more area under the curve than any other series of camshafts. This means more throttle response, quicker acceleration, more vacuum and better efficiency. These factors, combined with maximum horsepower and torque, make Voodoo camshafts the perfect choice for a wide range of high performance applications.Retro-Fit Hydraulic Roller. Strong power increase in mildly modified engines with excellent throttle response. Will work with stock converter in 383-up c.i.. Likes 2000 RPM converter in 350 or less c.i. applications. Likes 3.23-3.73 gearing. Largest choice for inboard/outboard marine applications. Has noticeable idle and likes headers.
Advertised Duration (Int/Exh): 270/278
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .515/.530
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1800-6000
Includes: Cam & Lifters (#72330-16)
Part Number: 20120711LK
Previous Part Number: 60111LK
Jobber Price: $605.56
I would consider a couple of things before spending your hard earned cash, by the time you add springs, keepers, retainers etc... you're going to have close to $800-1k invested so you want to do your homework. I hate to keep beating a dead horse but you have to keep your compression ratio in mind especially when dealing with small bore/stroke engines. It's really easy to cam yourself into a real dog. Generally my concern would be giving up ground made by giving up too much with a specific cam. You said your rough calculations are that the engine should have 10.5 static compression. Using that figure along with engine dimensions, altitude and intake closing on the cam, the dynamic compression is 9.50+. That would be pretty darn high in todays world. Obviously there are other factors to consider such as chamber design, head and intake efficiency along with the cooling systems ability to control engine temperature. I think this may be a good camshaft for your build if you find that the static compression you are able to achieve is less than originally thought but that there may be another choice if you do end up with that much compression to start. Also, for that kind of coin you should have the option for just about any grind you can come up with so you do not need to settle for an off the shelf camshaft.
I have also seen different kits by Lunati that have everything and they are right about $800. By the time I get a flat tappet valve train that will take the high RPM, I will probably end up spending that much money anyway. With the money I saved get this race prepped short block for a mere $400, I have more money in the budget for a retrofit roller.
I will be running ported L98 aluminum heads which are a very good match for what this engine will be able to take in and the aluminum should help out with dissapating some of the heat. All the comparing, phone calls and dyno program calculators I have run countless cam types through, I will have to build a pretty radical flat tappet engine and then it won't be anywhere street friendly. I just want my car to run respectfully for what it is and be able to drive it to the track, good running street/strip car that doesn't need a trailer to get there.
I still haven't purchased it yet, I have time. I still have to port the heads and modify the block to oil the top end like a regular small block. The other thing I have at my disposal is a friend who is an engine builder. He has his own engine machine shop in his shop. He is restoring his dad's BB/FC alcohol funny car and building the engine himself. He is also going to run an early 60's dragster with a nasty little small block. He learned and worked at a very well known engine builder in our area. I will certainly take his guidance because I have seen his skills and knowledge.
Alright engine gurus, how close to the bore should the fire ring of your head gasket be to the bore ? Due to the scalloped shapes at the top of my bores, the head gaskets I bought are right at the edge of them. I don't have a picture at the moment but thought I would ask first. I may be limited to a certain bore/combustion chamber shape since this was done to the block, so it brings up another question: How thin of a had gasket can I run with aluminum heads ?
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