pishta
I know I'm right....
Magnums are a great choice, (keep the 1.6 ped rockers) the original valve covers even fit. Any head gasket you find nowadays will have a huge 4.08 or greater fire ring.
Rebuilding a 65 273..I need some help.
- Thread starter jdhasa65cuda
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Ok. It sounds like more work than it's worth for me. I'll just prep the heads and do a nice valve job and put new springs on them. Thanks for the advise.
Your machine shop will let you know what you need whether if be new valves and or seats. A little larger valve won't make that much difference on a low compression street engine. A nice 3 angle and back cut valves may do you more good. Every little thing helps but where do you start and stop.
Do you think the voodoo hyd flat 220 226 cam will work well with the 273? I been building BB for the last 40 years and just starting to familiarize myself with the La engines. Also I plan to run Rhoads lifters. I have ran them in the past with great success. Thoughts on this combo with a performer and 600 performer?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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from; Large valved 273
"See here for a 675 chamber on a stock 273 bore; you can see the shadow line of the overhang of the chamber. (The white disc is a simulated 2.02" valve head.)"
Here you can see the distance between a 2.02 and the 1.5 exhaust valve is pretty far apart; looks to be ~.200?
An .188 is only .07 smaller on the radius or a tic over 1/16 inch. I think it's easy to see that 1/16 off the cylinder side of the white paper disc is still not inside the bore, even if you add the .030 for half the overbore
In other words your bores will have to be notched even for the 1.88s.
"See here for a 675 chamber on a stock 273 bore; you can see the shadow line of the overhang of the chamber. (The white disc is a simulated 2.02" valve head.)"
Here you can see the distance between a 2.02 and the 1.5 exhaust valve is pretty far apart; looks to be ~.200?
An .188 is only .07 smaller on the radius or a tic over 1/16 inch. I think it's easy to see that 1/16 off the cylinder side of the white paper disc is still not inside the bore, even if you add the .030 for half the overbore
In other words your bores will have to be notched even for the 1.88s.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Yur asking the wrong guy....... I run a 360,lol
A 220/110 cam is a nice cam in a 360 if a little conservative.
To run a 220 FT-hydro in a 273, I think the builder will need to have all his ducks in a row, and packed together tightly,lol..
Yup. I'll stick with the 1.78 as long as they aren't sunk. It runs perfect so I assume they freshend up the heads when they rebuilt the engine. This is all I have to go by as to what was done to it. An engine tag.
The lifters should get it closer to 205 at idle. I'm hoping that leaves it drivable still.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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are you the OP? I'm getting confused.
OK, let's back up, you have a rebuilt 273 and you want a little more power? You came in the middle ofsomeones 318 thread and it gets a little confusing. I don't remember the specifics. Do you have a 2 barrel or 4 barrel? Single or dual exhaust. A 4 barrel , a nice set of duals, and recurving your distributor will do you more good than a half point of compression slightly larger valves and a voodoo cam.
Nope
I hijacked the thread that was already started about the 273 heads to get the info I was looking for without starting another thread about the same stuff. I am the one that asked about running the 1.88 and 1.6 valves in the 273 heads on a 273. I decided to stay with the 1.78. But you touched on my cam spec so I asked your opinion on it. The Rhoads lifters will reduce my dur at idle by 15 deg at .050. They have worked for me in the past to tame cams at idle and 205 dur at .050 at idle should run fine. lol. I hope
I have a 273 .060. It was a 2 brl engine that was rebuilt. I want a little more power. It already has a recurved elect dist, a performer manifold and 600 performer carb and dual exhaust. I'm thinking about adding the cam and valve springs to compliment the cam.
I'm sorry. I apoligized for hijacking the thread when I started my first post but i'm sure it got confusing. Thank you and Toolman for all the help. Even if you didnt know you were helping me. ;)
All good as long as we are on the same page. You want a cammed up hotrod or just a good running 273? 273's and 318's can be over cammed pretty easy. You already have the low compression and small valve/small port heads. Those are your limits. Automatic or stick? What year and what car?
67 Barracuda. A-500 1700 to 2100 stall, 3.91 gear with low gears in the trans first 2 gears. I can go down a cam size if that best for my build. I just think it should pull to atleast 5000
Sounds like you have all the goodies to go along with except you don't know what compression/pistons for sure and no idea what cam is in it now. The cam grinders tech line may be your best bet. Because of your small cubes, compression, and heads they will recommend something pretty small I imagine. You don't want to over cam and go backwards on the power.
I wouldn't worry about pulling to 5 g's. 273's are a tough call because they have their limits. You are pretty much there. You can put a cam that works to 5000 and springs to match but your heads can't handle a ton of rpm. Too big of a cam turns it into a dog at lower rpm where you need it the most. There's some good running 273 cars out there but probably not much more than yours. The very few A body race cars running 273's are pretty serious pieces. They probably run 13-1 compression or more with .650 lift cams and big heads with a lot of machining to go along with. Like I mentioned, contact a few cam companies and see what they recommend.
The Isky E4 is rated to 5500 using their dual springs but it might not be much bigger than what you have. The E 3 and the Schneider cams are a bit bigger. Just sayin'
Here's a thread that is going right now about a 273 cam. Lots of good information and recommendations there especially the last page. [WANTED] - Help with Solid Cam?
What heads do you have?
Or a quote from 65Dartman
Today at 7:28 AM#1504
65 DartmanFABO Gold MemberFABO Gold Member
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NewI ordered my cam from Jim @ Racer Brown. We spent about an hour on the phone talking about the engine, transmission, rear end and general body, the major difference was I was houng hydraulic rather than solid. His recommendation was a cam similar in specs to the 273/235 with some tweaks. It’s listed as .410 lift on both intake and exhaust, 202 duration on both @.50 (nominally 262) with a 106 centerline. He said I will like the way the motor performs. He said if the motor was over cammed, it would be a dog.
Today at 7:28 AM#1504
65 DartmanFABO Gold MemberFABO Gold Member
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NewI ordered my cam from Jim @ Racer Brown. We spent about an hour on the phone talking about the engine, transmission, rear end and general body, the major difference was I was houng hydraulic rather than solid. His recommendation was a cam similar in specs to the 273/235 with some tweaks. It’s listed as .410 lift on both intake and exhaust, 202 duration on both @.50 (nominally 262) with a 106 centerline. He said I will like the way the motor performs. He said if the motor was over cammed, it would be a dog.
I don't think I heard a number but probably 920's. "On a 67 273 2v head." is what he described.
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67 heads should be closed chamber 920 castings. Guys racing 273's, not me, have said cut down 1.88 to 1.84 will work without being shrouded in 920 chambers. I would not bother with the 1.60 exhaust valves. I have run 1.88 intake intakes with 340 J heads on my +.040 273, but I centered the chambers over the bores with offset dowels, no bore notch. Worked great with a stock 340 cam if that helps, but I was running 10.5:1 pistons. Now, I just get a custom solid cam from Racer Brown and be done. You should already have the solid lifter rocker set up.
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