Summit CT-101 / Elgin 1091p

[F-BIRD'88]

I switched from my fully ported 4416 heads 1.94x1.60 to a set of fully ported GM 062 vortecs and the differnce was significant.
My 305 heads were not shabby at all but the Vortecs are just a lot better design. Your TFS heads should rock. These can be inproved further with soome hand porting. But for these get a Pro wtih experience and a flow bench to re work as they are already designed and cast well.
It will be like bolting on a after burner compared to your 305 heads. Use those heads on something else that needs the small size valves.
Did you ever test this engine at the track in the car? ET--- MPH??

My fully ported 305 heads (234 cfm) (as high as 242 cfm) will outflow a stock as cast GM 062 vortec head (228cfm) but the Vortecs are still Better.
The 305 heads are what they are. CarNut1 Charlie gets even more flow with even larger valves than I have used in the past.
You can look up his posts here and videos on You tube.

[F-BIRD'88]

I would use one of the cams I suggested ( or stay with the current Isky hyd cam) VS that Summit 256/264 camshaft with the TFS Super 23 * aluminum heads also.

[Monza355]

Change the heads and keep your current camshaft. It will pick up significantly

[rfoll]

Could you better express and define which part of the power band you want to see an increase output at?
What are the valve sizes on those 305 heads. They look small. (1.84"x1.50").
The summit CT-101 is going to add top end power 4500++rpm mostly VS your current cam.
But if the heads are chocked up it won't be realized. ( Having done these heads numberous times I know there is a critical area(s) deep in the port that need addressing to open up the Minimun cross sectional area. "opened up". This is critical to both HP and TORQUE. Especially on a hungry 400 cid SBC. I'll bet that revisiting your heads can buy big gains.
I don't think your compression ratio is near as high (11:1 cr) as you think with 400 dish pistons and those heasds (58-60cc).

Intake manifold is...________.

I used the high lift version .537 .557 of that 256/264 106LSA solid cam on a 350 with ported 4416 heads (1.94x1.60) at a true 12.65:1 cr.
It was all top end ( relative) In that motor in the car #3530 4.10's 3600 10"B&M stall big single plane ( strip dominator) I believe
I would have done slightly better using the smaller CT-108 cam. The big 256/264 cam would have wanted more gear 4.56 and a racing converter 5000 stall+/-. It was strong but I believe these changes would have made in stronger overall. On the street..

4.10's 3600 stall 248/254 106 lsa or a crane "saturday night" 244-252 106 cam (isky 201524 or #201534) and a dual plane RPM with a spacer. (More torque right at the 1/4 mi. launch (3600 stall speed)

On the cam I believe (Mike Jones) Cam King (Jones Racing Cams) has beauti SFT cam lobes right there, for this.
Does not cost you a dime to consult him in this and you ARE ensured of a high quaility product (camshaft and "Centra - Lube" lifters) VS a Elgin-Summit cam. I'd hear him out first before hitting the switch.

Thanks for the detailed response.
In terms of power band, 4000-6000 is where I want to see better power, I probably won't rev it any higher than 6500.

Valve size is the stock 1.84 x 1.5, but they are new Elgin valves.

My dished pistons are 12cc SpeedPro's, with a .005" deck clearance and .039" gasket, which is where I got the 11:1 ratio from (still could be off somewhere in my calculation)

Intake manifold is a Performer RPM knock-off, plenum cut down with 1/2" open spacer, with a 750 annular-booster carb from a builder in PA.

I recently measured a bore with the Speed Pro 12 cc dish piston. With a 70-72 cc chamber and an .005" deck, compression comes out around 10:1. Figure roughly 0.10 compression point per cc change, so you you should be near 11:1. But, in the case of a 58 cc 305 head or a performance head with a 64 cc chamber or larger, the flow will trump the compression by a long way on a 406. Add that better flowing heads require less cam and you save the price and also the headache of breaking in a new cam. Is your Isky cam the one with only .450" lift? If so, it's also a cork in the system.

[F-BIRD'88]

Those Isky .450" lift circle track hyd cams punch way above their weight.

[crawdaddy_johnson]

Could you better express and define which part of the power band you want to see an increase output at?
What are the valve sizes on those 305 heads. They look small. (1.84"x1.50").
The summit CT-101 is going to add top end power 4500++rpm mostly VS your current cam.
But if the heads are chocked up it won't be realized. ( Having done these heads numberous times I know there is a critical area(s) deep in the port that need addressing to open up the Minimun cross sectional area. "opened up". This is critical to both HP and TORQUE. Especially on a hungry 400 cid SBC. I'll bet that revisiting your heads can buy big gains.
I don't think your compression ratio is near as high (11:1 cr) as you think with 400 dish pistons and those heasds (58-60cc).

Intake manifold is...________.

I used the high lift version .537 .557 of that 256/264 106LSA solid cam on a 350 with ported 4416 heads (1.94x1.60) at a true 12.65:1 cr.
It was all top end ( relative) In that motor in the car #3530 4.10's 3600 10"B&M stall big single plane ( strip dominator) I believe
I would have done slightly better using the smaller CT-108 cam. The big 256/264 cam would have wanted more gear 4.56 and a racing converter 5000 stall+/-. It was strong but I believe these changes would have made in stronger overall. On the street..

4.10's 3600 stall 248/254 106 lsa or a crane "saturday night" 244-252 106 cam (isky 201524 or #201534) and a dual plane RPM with a spacer. (More torque right at the 1/4 mi. launch (3600 stall speed)

On the cam I believe (Mike Jones) Cam King (Jones Racing Cams) has beauti SFT cam lobes right there, for this.
Does not cost you a dime to consult him in this and you ARE ensured of a high quaility product (camshaft and "Centra - Lube" lifters) VS a Elgin-Summit cam. I'd hear him out first before hitting the switch.

Thanks for the detailed response.
In terms of power band, 4000-6000 is where I want to see better power, I probably won't rev it any higher than 6500.

Valve size is the stock 1.84 x 1.5, but they are new Elgin valves.

My dished pistons are 12cc SpeedPro's, with a .005" deck clearance and .039" gasket, which is where I got the 11:1 ratio from (still could be off somewhere in my calculation)

Intake manifold is a Performer RPM knock-off, plenum cut down with 1/2" open spacer, with a 750 annular-booster carb from a builder in PA.

I recently measured a bore with the Speed Pro 12 cc dish piston. With a 70-72 cc chamber and an .005" deck, compression comes out around 10:1. Figure roughly 0.10 compression point per cc change, so you you should be near 11:1. But, in the case of a 58 cc 305 head or a performance head with a 64 cc chamber or larger, the flow will trump the compression by a long way on a 406. Add that better flowing heads require less cam and you save the price and also the headache of breaking in a new cam. Is your Isky cam the one with only .450" lift? If so, it's also a cork in the system.

Yes its the .450" lift rule cam

[crawdaddy_johnson]

Those Isky .450" lift circle track hyd cams punch way above their weight.

Agreed, I was looking at the Isky lobe master list and this 288/244 hyd lobe comes pretty close to their older solids in the .100/.200 duration range

[rfoll]

For a 400 I would for sure put 1.6 rockers on it.

[RCJ]

Years ago we raced in a class with that cam and vortex heads. Made over 500hp on a 350. Had a custom cam ground just for our motor. It might have made 5hp more . Going to shaft rockers netted more hp

[rfoll]

" I'm tempted to pick up a pair of TFS 195cc "super 23" heads" These would almost be a waste of money with a .450 lift cam. At the same rpm the 400 will need to move 14 percent more air.

[F-BIRD'88]

" I'm tempted to pick up a pair of TFS 195cc "super 23" heads" These would almost be a waste of money with a .450 lift cam. At the same rpm the 400 will need to move 14 percent more air.

True. If you want maximum engine performance GAIN when swapping to those good heads you'd want to re-cam the engine with higher valve lift than .450". It will still run good with that cam. It will run BETTER with a different cam.
I'd use that Isky cam and the ported 305 heads on something else.
Say a low buck Poor Man's Racer 350...or. A low $$ street cruiser where you're more concerned with sound and butt dyno "light to light" GLH experience.. The lil .450" Isky can be run with high ratio rocker arms to increase the valve lift. 1.60:1 ratio rockers give you a street friendly .480" net valve lift.
Just right for ported 305 heads on a 350. Make sure that that Isky 288/244 .450" 106LSA cam is installed well advanced (100/102 intake CL) if you want TORQUE !.

[barnym17]

I have used the ct-108 in a 355 with 11 to1 ported 292 heads(ancient and likely worn out but same with all 3 cams) same everything but cams in a 3000lb malibu.Car has 5.13 gear 28x10 slicks,glide with 4500 stall. Engine uses old strip dominator with 800dp Holley pretty cheap old bracket beater.
1.Cam was comp 292h car ran 8.0 in 1/8th around 86 mph if memory serves.
2.Cam was ct 108 she ran 7.70s at around 89 mph
3.Cam is crane solid roller 258 @.050 .630 lift Intake 258 @.050 .630 exh 106 lobe sep in on 106 c/l (old dirt latemodel cam had laying around) runs 7.40 at 96 last outing.
Appropriate springs were used on each cam played with shift points some these were results. 292h ended up liking around 6500,ct 108 the same 6500 altho it ran good to 7000 rpm. The crane likes some rpm I shift it at 7200 probably faster if I raise rpm some more but it's just a stock rodded cast crank toy I have had since the 90's and don't wanna run over any parts lol.

[rfoll]

A 406 is a quantum leap above a 355. I had spun a bearing on my 406 do to a oil pressure issue. I resurrected my 355 using the heads, (034 Bowtie),Performer rpm air-gap intake, and 780 carb from the 406. Same car, gears, converter, tires etc. While thinking about making the 355 faster, I decided to regrind the 400 crank and put it back together. All the same stuff came off the 355 and went back on the 406 along with a more suitable cam. Crane HI-244/3534-6. 244@.050, .530 lift. It was a full second faster. The aforementioned low lift Isky might be fine with 305 heads, maybe even Vortecs, but after that it's time for a reality check.

[crawdaddy_johnson]

I have used the ct-108 in a 355 with 11 to1 ported 292 heads(ancient and likely worn out but same with all 3 cams) same everything but cams in a 3000lb malibu.Car has 5.13 gear 28x10 slicks,glide with 4500 stall. Engine uses old strip dominator with 800dp Holley pretty cheap old bracket beater.
1.Cam was comp 292h car ran 8.0 in 1/8th around 86 mph if memory serves.
2.Cam was ct 108 she ran 7.70s at around 89 mph
3.Cam is crane solid roller 258 @.050 .630 lift Intake 258 @.050 .630 exh 106 lobe sep in on 106 c/l (old dirt latemodel cam had laying around) runs 7.40 at 96 last outing.
Appropriate springs were used on each cam played with shift points some these were results. 292h ended up liking around 6500,ct 108 the same 6500 altho it ran good to 7000 rpm. The crane likes some rpm I shift it at 7200 probably faster if I raise rpm some more but it's just a stock rodded cast crank toy I have had since the 90's and don't wanna run over any parts lol.

That's awesome, I love hearing about simple but smart combos that run hard.

[crawdaddy_johnson]

Years ago we raced in a class with that cam and vortex heads. Made over 500hp on a 350. Had a custom cam ground just for our motor. It might have made 5hp more . Going to shaft rockers netted more hp

Out of curiosity how much compression were you running on that motor?