76cc sbc head

[SCOTI]

I'm looking for the latest excellent flowing head in a 75/76cc chamber for a flat-top 406. I'm curious is there's new stuff I haven't heard about. Let me know what you know . . ....

[67ZL1]

I have a set of AFR 210's on top of my 406 solid roller engine. haven't fired it up yet.

[SCOTI]

210's are too much.

I'm looking for something that builds torque on 'true' pump gas motor (or.... a smaller runner size that still flows). I have a set of AFR-190 streets but the chambers are 68cc which is too small for pump gas & torquem on a flat-top 400 based engine. I've been looking @ the AFR-Eliminator 195's in a 75cc chamber but was curious if anything else was available that I might not know about.....

[grayw0lf]

What's the estimated octane rating on the 406 w/ 76cc AFR's? Can you still run 87 octane?

[SCOTI]

Originally Posted by grayw0lf

What's the estimated octane rating on the 406 w/ 76cc AFR's? Can you still run 87 octane?

Depends on the piston design. Dished? No problem.
Flat top? Maybe. The flat top would be do-able w/some 91 octane.

[swb85]

Originally Posted by grayw0lf

What's the estimated octane rating on the 406 w/ 76cc AFR's? Can you still run 87 octane?

Depends on the valve events of the cam. Close the intake valve late enough and 87 is doable. Lot of work just to save ~30 cents/gallon.

[bigsnookmaster]

I run a flat top 406 w/5.7 rods and 70cc edelbrock Victor Jr. heads, thermal coated piston and combustion chambers,and run 93 octane pump gas.No problems at all, I believe the coatings contribute to this working. My .02

[SCOTI]

Originally Posted by bigsnookmaster

I run a flat top 406 w/5.7 rods and 70cc edelbrock Victor Jr. heads, thermal coated piston and combustion chambers,and run 93 octane pump gas.No problems at all, I believe the coatings contribute to this working. My .02

What size cam?

[Marv D]

Originally Posted by SCOTI

210's are too much.

.....

Are you thinking the 210's are too much $'s ??? or too much runner for a 406??? I sure wouldn't want anything smaller than a 200-210cc runner on a 406, in anything less than a towtruck motor myself. But that's just my opinion.

A 406 with a stock 22cc "D" dished piston, sitting 0.025" in the hole will have 8.96:1 compression with a 68cc chamber and a 0.041" FelPro gasket. The "D" dish will keep the quench tight, open the total chamber up for the low compression your looking for. Pistons are a lot cheaper than heads

[SCOTI]

Originally Posted by Marv D

Are you thinking the 210's are too much $'s ??? or too much runner for a 406??? I sure wouldn't want anything smaller than a 200-210cc runner on a 406, in anything less than a towtruck motor myself. But that's just my opinion.

A 406 with a stock 22cc "D" dished piston, sitting 0.025" in the hole will have 8.96:1 compression with a 68cc chamber and a 0.041" FelPro gasket. The "D" dish will keep the quench tight, open the total chamber up for the low compression your looking for. Pistons are a lot cheaper than heads

210's are overkill for a mild street motor that's being designed for torque, hence "too much". If you're building everything else to benefit that air flow, they're great. I agree on it costs less to change pistons vs. heads. But, unless you're in the thick of building motors regularly, new stuff always comes out that sometimes makes what 'was' the hot ticket, outdated.

[bigsnookmaster]

Hey SCOTI, I run a Comp 286 X-TREME mechanical roller. I believe it's a .578 - .584 lift advertised .250 at .050, and a 110 lobe center

[SCOTI]

Originally Posted by bigsnookmaster

Hey SCOTI, I run a Comp 286 X-TREME mechanical roller. I believe it's a .578 - .584 lift advertised .250 at .050, and a 110 lobe center

I'll bet that cam has alot to do w/living on 93 oct w/o pinging. Runs good huh?

[bigsnookmaster]

Real good!

[Wild83C10]

Originally Posted by SCOTI

210's are too much.

I'm looking for something that builds torque on 'true' pump gas motor (or.... a smaller runner size that still flows). I have a set of AFR-190 streets but the chambers are 68cc which is too small for pump gas & torquem on a flat-top 400 based engine. I've been looking @ the AFR-Eliminator 195's in a 75cc chamber but was curious if anything else was available that I might not know about.....

How did you determine that the 68cc heads are too small for pump gas? Have you determined you static CR? I also disagree with you on the "210 is too big". Just about any engine builder will tell you that the bigger inch SBC need the 210cc runners. What makes you think you wont have enough torque? You can use the cam and intake to get the power band you want.

I have a 383 with AFR 210cc runners and 65cc chambers. I run a Victor Jr and a decent duration roller cam (240ish @050), which doesn't build all that much low end torque. More torque then the suspension can handle. I have caltrac, drag radials and adjustable shocks and additional weight in the rear. Runs on 91 octane all day long, 7k rpms, 36 degrees total.

Either way the AFR heads are great and either 195s or 210 will be your best bet. I would go with the 210 though.

[SCOTI]

I have a DCR calculator program. I cross reference the info from that to an engine link (for piston combos) to get the static compression.

408
Hyper flat tops, -6cc. .025" in the hole
.021 head gasket (.046 quench)
AFR-190's 68cc
Lunati hyd 300/300; 246/246; 108lsa/104ICL

8.10 dynamic CR
10.2:1 static

I know 10.2 is capable w/an alum head on 93-pump gas. I was just looking for other options as well. My initial thought was to swap some forged pistons in w/a little dish & a smaller cam but like stated.... educating myself on possible new products is the cheaper option for now.

It's in a truck so useable torque is what I'm looking to build.

[swb85]

You're nowhere near the limit of compression for 93 pump fuel with alum AFR heads. I'm running 8.4:1 dynamic compression with IRON heads on 91 octane......runs like a striped ape with zero detonation. Compression builds torque, run as much as you can get away with. If your SCR/DCR numbers above are accurate, I'd zero deck the block and run a .039 gasket....tighter quench for increased detonation resistance and bump the DCR up a little. I've run as high as 8.85:1 DCR on 93 before with no problems......

[Outlaw72]

FWIW....I had a 408 once in my 72 running a dart 200cc iron eagle head. Compression was around 10.4:1 and used pump gas all day long. The best way to determine your runner IMO is to know what RPM's you will run. If you shift above 6,200....then a 220cc runner head is not overkill at all. If you are below this RPM a 200cc runner head will be fine. A 220cc head will not benefit you at all unless you spin the engine higher than 6k - 6.2K

[SCOTI]

Originally Posted by Outlaw72

FWIW....I had a 408 once in my 72 running a dart 200cc iron eagle head. Compression was around 10.4:1 and used pump gas all day long. The best way to determine your runner IMO is to know what RPM's you will run. If you shift above 6,200....then a 220cc runner head is not overkill at all. If you are below this RPM a 200cc runner head will be fine. A 220cc head will not benefit you at all unless you spin the engine higher than 6k - 6.2K

I agree. The 'exception' would be the only time the motor saw the high side of 6K. 99% of the rest of it's life is going to be spent on street duty.

I think I'll use it as is & see how it goes. I've never had much exposure to the 350 vs. 400ci combo's w/the same cam. Back in my younger years, my roomate had a 69 short fleet, 406 w/a set of mild stock heads, stock style pistons, Comp 292H cam, t-350 w/a kit, 3.73's & 325-50-15's.... I remember it pulled like a freight train. This should have more compression & better airflow capabilities for an even better experience.

Thanks for everyone's input & experience.

[Bowtie67]

Seems like an awful big stick and wanting something with lowend tourque & drivability, Even the CR @10.2 and still having an 8.2DCR with this cam seems a bit high. I run 10.5cr in my 427sbc with some victor 215 heads, cam is a custom Luntai roller 239/242@050, 290/294 adv with a112LC and have absolutely no issues with pinging or detonation, I was also running the Crower 236/240, 286/292 110LC roller cam without any issues, truck had mega lowend and upperend tourque, I just wanted something not quite as radical, although listening to it you could really tell much of a difference. But it did have a much better manner at cruise speeds without having to jump in it to keep it cleaned out.

On anaother thought where did you get the specs on the cam needed to check your DCR, Lunati does not put .006 timing specs that are needed for checking your DCR. If your using the .050 your DCR is wrong and if it isnt your DCR is really right on for running pump gas unless of coarse your wanting to run 87 octane..

[SCOTI]

I have a DCR file/program that calculates everything out so I'm not using any manufacturers specs specifically. I really don't want to run that cam & piston combo for reliabilty & torque..... It's what was already there & I was planning to change it but now I'm considering other options.

[6t9ls1]

hey man for what its worth i was building a Gen 1 406 and jumped the gun before consulting anybody and bought a set of trick flow 195's with 76cc chambers only too be told by my machinest that it would be a total dawg because those runners would more or less choke the motor. Engine specs were as follows: stock block .30 over kieth black pistons at 10.8-1 comp, comp solid roller .552 int. .564 exh. 24?-25? dur. on a 110, pete jackson gear drive, harland sharp roller rockers. I took his advice and switched to a 350 block bored .40 with kieth black pistons same compression.

As far as heads the AFR are very good pieces. You may want to check out Total Engine Airflow. They take aftermarket and stock heads and rework them. They do killer work.

[Bowtie67]

Originally Posted by SCOTI

I have a DCR file/program that calculates everything out so I'm not using any manufacturers specs specifically. I really don't want to run that cam & piston combo for reliabilty & torque..... It's what was already there & I was planning to change it but now I'm considering other options.

As of the past few years I have only been running roller cams and probally wont be going back to the flat tappets due to todays oils, and the power to be had by roller cams. There are some really nice roller cams that I can think of right off hand for your combo.

Comp 224/230@.050 276/282 HR the have this cam with a 110LC and a 112LC the 112 is a marine cam, I ran the marine cam in a 413 with 10.5cr, lots of great tourque, fun not real radical, good sounding cam.

If your wanting something radical try running the crower I listed above, the cam is a beast massive tourque, you will be rattling windows and melting tires. I was going to have them grind me this cam but put it on a 113LC, but after gettimng jerked around for an hour on the phone I called Lunati.

I havent ran this cam but was very tempted in my 427, comp cams EFI xtreme h/roller the specs @.050 230/236 on a 114LC and uses 1.6 rockers (this could be considered nice a sleeper cam and because of its LC of 114 would make a very nice cruzeable cam) Check with comp to see if this cam would have any type of lope to it, if it does it probally not much.

[turp mcspray]

For a cam vs. compression comparison...I built a 406 for my 72 blazer several years ago. I wanted low end, due to the weight and 36" swamper tires. I had the block decked square, the pistons ended up about .005 in the hole. I used 487x heads, (factory iron) flat tops, short rods, and an Isky 270 mega cam, advanced 4 degrees. It worked out to right about 10.0. My cranking compression is 195lbs. I run 91 octane and the only time it ever pings is if I were to lug it hard while going up a big hill in 3rd gear of my th350, when it's 95 or hotter out.
Btw where can I find a dcr program?

[fryco]

I must of missed somthing.... the title of the page is "racing and hipo" not pump gas punks w/open chamber heads.. we should be talking about $5-20 per gallon gas (and how to burn more of it)

i'm kidding around, just a observation.

[turp mcspray]

Originally Posted by fryco

I must of missed somthing.... the title of the page is "racing and hipo" not pump gas punks w/open chamber heads.. we should be talking about $5-20 per gallon gas (and how to burn more of it)

i'm kidding around, just a observation.

You MUST have missed something. Nowadays their running single digits on pump gas! LOL!