Tunnel rammed 23* 421sbc
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Re: Tunnel rammed 23* 421sbc
The cam duration is 20 deg too short for max power on this engine.. It will run with your cam but you are leaving a lot on the table. Tunnel Rammed engines like to eat. Let it eat.
Use 100 octane unleaded . It will go faster and last longer too..
Use 100 octane unleaded . It will go faster and last longer too..
Re: Tunnel rammed 23* 421sbc
I have a very similar TR 427 in my 5 speed 79 Camaro. Smaller heads (AFR 210's) but bigger cam (SKU 12-863-9) 263/272 SR. Compression is in the 11:1 range. Runs great on 91 oct made over 600 hp on the engine dyno. Great engine, I drive it daily when weather allows.
79 Cmaro, 427 sbc, Tunnel Ram Dual Quad with Eddy carbs, AFR 210 Race Ready heads, 263-272 @.50 Comp solid roller cam, 4.10's and a faceplated Tremec TKO 600.
65 Beaumont 406 tunnel ram faceplated TKO600
65 Beaumont 406 tunnel ram faceplated TKO600
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Re: Tunnel rammed 23* 421sbc
Ha has a tunnel ram. The smaller cam will make more torque everywhere, and the tunnel ram will allow it to rpm more than a single plane..
My advice... STFU about 100 octane gas. Leave the 60s behind you. His combo should make mid to high 600s and be a fun weekend cruiser.
Re: Tunnel rammed 23* 421sbc
Keep you "advice" to yourself. Or take a bit of it.mt-engines wrote: ↑Mon Jun 14, 2021 11:46 amHa has a tunnel ram. The smaller cam will make more torque everywhere, and the tunnel ram will allow it to rpm more than a single plane..
My advice... STFU about 100 octane gas. Leave the 60s behind you. His combo should make mid to high 600s and be a fun weekend cruiser.
High torque equals high cylinder pressure.
Wants octane to protect an expensive 11.5:1 cr engine from detonation on the street where operating conditions change a lot..
Re: Tunnel rammed 23* 421sbc
if you're referring to my set up, it gets 22 imperial mpg (20 us gals per mile) at 70 mph. Also has good passing power, lol54chevkiwi wrote: ↑Mon Jun 14, 2021 10:17 am Oh yea, yours is absolutely a setup ive Paid attention to!
79 Cmaro, 427 sbc, Tunnel Ram Dual Quad with Eddy carbs, AFR 210 Race Ready heads, 263-272 @.50 Comp solid roller cam, 4.10's and a faceplated Tremec TKO 600.
65 Beaumont 406 tunnel ram faceplated TKO600
65 Beaumont 406 tunnel ram faceplated TKO600
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Re: Tunnel rammed 23* 421sbc
By my calculations Eric has given you enough cross section to peak at 7000 so peak torque should be around 5500rpm give or take,54chevkiwi wrote: ↑Sun Jun 13, 2021 7:59 pm Burns spec’d tri-y headers 1-3/4 10.5” stepped to 1-7/8 10.5” primaries into 2-1/8 secondaries for 10.5” with 2-3/8 choke into a 4” single tailpipe or 3” twin pipes.
I really liked the fat mid range of the single pipe on the last engine.... but im thinkin i may go regulat twin pipes this time, i think itll have too much power already without needing every last bit
Not sure how much experience you have had with decent size converter but I would be going there for sure even if you don't go a real low rear gear,I have used my 8" 5600 in mild combos that peak at 6000 and they always run quicker at the track.
I would consider a twin 3" exhaust system as well just my opinion.
steve c
"Pretty don't make power"
"Pretty don't make power"
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Re: Tunnel rammed 23* 421sbc
steve cowan wrote: ↑Tue Jun 15, 2021 5:46 amBy my calculations Eric has given you enough cross section to peak at 7000 so peak torque should be around 5500rpm give or take,54chevkiwi wrote: ↑Sun Jun 13, 2021 7:59 pm Burns spec’d tri-y headers 1-3/4 10.5” stepped to 1-7/8 10.5” primaries into 2-1/8 secondaries for 10.5” with 2-3/8 choke into a 4” single tailpipe or 3” twin pipes.
I really liked the fat mid range of the single pipe on the last engine.... but im thinkin i may go regulat twin pipes this time, i think itll have too much power already without needing every last bit
Not sure how much experience you have had with decent size converter but I would be going there for sure even if you don't go a real low rear gear,I have used my 8" 5600 in mild combos that peak at 6000 and they always run quicker at the track.
I would consider a twin 3" exhaust system as well just my opinion.
Yea its a 9” jakes converter currently. I asked him about the new combo, he said to try this one first as it might already do what i want. Sound advice i thought. I mean, itll surely be less than optimal but at least ill have a benchmark for comparison.. gotta know where youve been to know where youre going type thing, you know?
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Re: Tunnel rammed 23* 421sbc
Relief for connecting rods. Done with the 1” belt sander and smoothed with the scotchbrite wheel. This is 2 and 6..
1 and 5 need about .060 more than this, these only just cleared this amount of relief
1 and 5 need about .060 more than this, these only just cleared this amount of relief
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Re: Tunnel rammed 23* 421sbc
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Re: Tunnel rammed 23* 421sbc
Hey so i probably shouldve specified this early on, but im not doing anything here thats revolutionary or reinventing the wheel, im just documentimg what im doing, mainly for the benefit of people who want to figure out how to do something. Like, i sometimes wanna see something close up so im offering this to other people on this thread. Thats why i posted it here instead of the other engine forum which needs membership and logging in to view.
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Re: Tunnel rammed 23* 421sbc
Checked piston to valve.. cam degreed perfectly, i got .050 intake and exhaust where its meant to be and .015 intake and .09 exhaust advanced 2 degrees. Both ways with checker springs, checker pushrods, dummy gasket and zero lash with a dial indicator..
I checked with a running pushrod and the actual springs and got like .110 on both with lash and clay method trying not to squish the clay with calipers.. i can extrapolate ill have about .065 and about .140 2 degrees advanced...
I got a pair of lindytools relief cutters, i couldve cut the pistons at work but figured this wouldve been convenient, as we are too busy at work to have a machine available right now.. turns out i didnt need to cut them yet... i dykem’d the pistons and rubbed the top with the cutters, valve angles matched the piston tops perfectly,
i might tickle them radially a bit... in any case ill double check p/v when the shortblocks together and heads are resting in place
I checked with a running pushrod and the actual springs and got like .110 on both with lash and clay method trying not to squish the clay with calipers.. i can extrapolate ill have about .065 and about .140 2 degrees advanced...
I got a pair of lindytools relief cutters, i couldve cut the pistons at work but figured this wouldve been convenient, as we are too busy at work to have a machine available right now.. turns out i didnt need to cut them yet... i dykem’d the pistons and rubbed the top with the cutters, valve angles matched the piston tops perfectly,
i might tickle them radially a bit... in any case ill double check p/v when the shortblocks together and heads are resting in place
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Re: Tunnel rammed 23* 421sbc
Carbs arrived courtesy of Braswell..
they sent me 1.36 x 1.69 4760s
Nice.
they sent me 1.36 x 1.69 4760s
Nice.
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Re: Tunnel rammed 23* 421sbc
You have more than enough P/V to not notch the pistons. You’d be throwing away compression.54chevkiwi wrote: ↑Sun Aug 22, 2021 6:17 pm Checked piston to valve.. cam degreed perfectly, i got .050 intake and exhaust where its meant to be and .015 intake and .09 exhaust advanced 2 degrees. Both ways with checker springs, checker pushrods, dummy gasket and zero lash with a dial indicator..
I checked with a running pushrod and the actual springs and got like .110 on both with lash and clay method trying not to squish the clay with calipers.. i can extrapolate ill have about .065 and about .140 2 degrees advanced...
I got a pair of lindytools relief cutters, i couldve cut the pistons at work but figured this wouldve been convenient, as we are too busy at work to have a machine available right now.. turns out i didnt need to cut them yet... i dykem’d the pistons and rubbed the top with the cutters, valve angles matched the piston tops perfectly,
i might tickle them radially a bit... in any case ill double check p/v when the shortblocks together and heads are resting in place
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Re: Tunnel rammed 23* 421sbc
Yea i bought those things before i properly checked just incase i needed to.. i was happy i didnt haveto. Thanks for your input, i appreciate the confirmation i was on the right track.