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283 tunnel ram?

11K views 23 replies 7 participants last post by  bsa_bob2 
#1 ·
I have a 30 Ford I'm building with 283 motor not sure if bored haven't tore it down yet but any way I was wondering what kinda of setup I would need to run a tunnel RAM heads cam and so on
 
#2 ·
I dunno if I`d want a tunnel ram on a 283, unless I was looking to rev the stink out of it. If you try this then I`d be modest on the carb size, around
390 cfm each. However before you do so you may as well strip it down and see what your working with before moving forward as you`ll likely need a 57cc head to keep compression up.
 
#6 · (Edited)
there are alot of factors that we may not know about your combo to further help you, but if you are panning on running a TR for the street, run a cam with at least 112 or more lobe angle mild lift and about 228-240 duration @.050.. Heads? cc's are they, intake runners? combustion chambers? and so on..Carberation is on of the more critical points on a TR for the street..The biggest thing is not to over carb the motor and with two 390's thats only 780 cfm, so with your small cube motor, this will help.. Buy a set of 390's vacuum secondaries!! like these here:http://www.allcarbs.com/detail.php?pid=891&mfgn=1&ctgn=71&stt=0&gb=2 they will be expensive, but these are already setup for a TR, just with minor tunning as you run..it will be alot more friendly to you.. It can be done!! just have to do some reasearch and buy the right products for your combo

hope this helps
 
#9 · (Edited)
The amount of cfm you be using on a 283 is not very high, You really do not need big heads. You can use 62CC 1.94 intake heads, but your compression will drop or replace the pistons. You will not get the torque response at the low end of the RPM on less you change the rear end gear ratio somewhere 390 to 410 gears or lower 1st gear on the tranny. You can try to get 1.94 57CC heads. The 283 needs compression. The $$$$ will start to add up. You be better off getting a 350 instead. :drunk:

Use this calculator to find CFM the 283 is pulling.
http://www.4secondsflat.com/Carb_CFM_Calculator.html

Use this calculator for compression ratio
http://www.csgnetwork.com/compcalc.html
 
#10 ·
Now that I`ve more time to post, I`ll fill in what I left out. when considering a combo, any combo, you have to consider that all pieces work together as a team to create the best power. That`s so to say, the intake and carbs go up, the rest of the combo has to go up with it, head flow, compression ratio, exhaust flow, ignition and especially the cam, which is usually what the combo is circled around. A 283 is a great small block, but remember, it`s not a very big small block in terms of cubic inches, a cam that would idle smooth in a 350 will lope in a 283. Next consider the 283`s short 3 inch stroke which isn`t great about low end torque developement so the cam pick will have a big influence on it, especially with a tunnel ram which isn`t designed for low end torque either. But since your dealing with a lighter weight street rod with the right combo you can have good low end torque and upper rpm power.
When you strip it down then you can tell what pistons it has, how far below deck they are and etc. 283`s came with 55 to 57cc chambers to keep compression ratio around a 9:1 to ratio. Once we know the compression ratio, plus the runners of the intake ports, placing together a combo from there is easy. Also keep in mind 283`s don`t need alot of intake port to be happy. What are the casting numbers of your cylinder heads? What are the valve sizes?
 
#13 ·
The motor has been gone threw and rebuilt but it has been a few years I didn't do it the man that did said he had a tunnel RAM on it once before but still I am 17 building my truck from the ground up and learning all at the same time so thank you for helping and if you need info to help me out ill tell you all I know
 
#14 ·
glad to see you want to learn this at your age!!! if you still can talk to the builder, get some detail info on the bottom end, like piston to deck clearence, that is how far the piston is in the cylinder when the cylinder is at Top Dead center, usually to measure this is take a carpenter sqaure and place it over the top of the piston, then take a feeler guage start about .020 and run it under the carpenter square, keep going smaller or bigger on the guage till you have a slight drag to the guage then take note of the reading. also what 327 heads do you have? casting numbers? if they are 291 last three digits they are 64cc chamber 160cc intake runners, or if they are 461 NOT 461x they are 62cc chambers 160cc intake runners.. Once we know where your deck clearence is, details on your heads, and pistons what type they are and brand if known..That way we can help figure your Static compression ratio which is piston volume cc's of the top of piston, heads {combustion chamber}then deck clearence in .000 if an inch and thicknes of your head gasket that you plan on using. most use a .040-.044 thick head gasket.. lg1969 is the man to talk to about setting up a TR for the street!! He has help me alot, and to set me up in the right direction
 
#17 ·
Okay sounds good. However, if your heads are 2.02 1.60 then I would bump down to 1.94 1.50. and there are 2 reasons for this. first is if the heads didn`t come with them and the former builder had them installed it`s likely the chambers were not swept, which means to have some material removed from the chamber wall to help reduce shrouding, the second problem is the 283`s 3.875 inch bore size is smaller than the valves are wide which creates bore shrouding so in this case you have double shrouding going on. I had a set of 041 castings that I held on to for years and I didn`t want to let them go, but the last time I removed them the guides were already wore out at 30,000 miles and the seats, which were not set up hardend for use with unleaded gasoline were really pounded down and needed replaced. A guy offered me $150 for those old hump heads and I quickly said sold and got rid of them money pits. If I were you I`d do the same to the hump heads you have. 64cc heads as they are on a flat top piston 283 with a standard head gasket and deck clearance your compression ratio is 7.9:1.
Throw a set of 57cc heads on it and it goes up to 8.6:1 which is better but not by much. If you sold your hump heads you could invest that cash into a set of these:
http://www.northernautoparts.com/ProductDetail.cfm?ProductId=438
These heads are made just for small displacement small blocks and they flow plenty so they would offer excellant performance.
Or if you want to take the cheap route find a set of 416 casting 305 heads, have`em built, stick`em on and go. With either head you could use a thin head gasket to get the compression ratio up to the 9:1 range if the engine has flat top pistons.
 
#21 ·
This is hijacking a thread or so it`s called. A new thread would have gotten the same results. However, if you have a 350 with 305 heads and flat top pistons with the correct compression height of 1.560, the ratio will be very close to the 11:1 mark. Running a thicker gasket will only make the problem worse due to the lack of quench. When the block hasn`t been decked, and the piston is sitting .025 below deck and you add in a thick head gasket from .040 and up the distance increases and there is no quench past .060.
The thicker gasket won`t be thick enough to lower the compression low enough to work without detonating itself to death in short order. To get it to work you`d have to slow the timing down so far it would be a slug.
 
#22 ·
yeah,

But one more thing since were so close here.

To achieve @ 9.5 to 1 CR on a 350 chevy street engine would it be the 64cc or 67cc heads?

I don't think it's the 72cc or 76cc heads.

Is there a good link that sorts this all out?

--------------------------

I apologize to the OP.. but this is where the guys in the know were hanging out at.
 
#24 ·
I installed a polished, single carb TR on my 283 back in 68, it was in a t-bucket.It would not run good at all , no matter what i did. I was told screen had to be put between the carb-- and the lower TR half- and it would work. I f you nailed it it would bog down abit. everytime, if you hit it from a roll this t--bucket would fly.So whatever you do follow these guys suggestions on"set-up" very closely.They look awseome when polished, good luck :thumbup: bob s
 
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