Okay, I took your advice so far now I need more if ya don't mind...

[L31MaxExpress]

Just for a civil discussion how is Chevrolet able to get advertised
345 HP @5000 RPM 396 LB/FT @3600 RPM out of the 395 marine cam, with STOCK vortecs, with LESS lift and only 9:4 compression than someone utilizing 1.7 rockers, larger 2.02 valves, better springs yada yada ....... the poster says 250 hp at the wheels which would be 300 at the crank using the standard 20% driveline losses...so 45 horsepower is still being lost somewhere in that "better" setup....detonation prone also says something is wrong somewhere......Im running a 10:1 marine cammed 360 with "305" TBI swirls, iron exhaust manifolds, a 160 stat , medium springs in my distributor and a carb and have no pinging ????

Hot Rod magazine threw one on the dyno "With an electric water pump and 1-3/4-inch-primary dyno headers and Flowmaster mufflers, the RamJet delivered better-than-advertised peaks of 413 lb-ft at 4,100 rpm and 364 hp at 5,000. Add power accessories, and that means GM’s numbers are about right on. Better yet, the torque curve is very flat, hovering close to the 400 mark from 2,500 rpm all the way to the horsepower peak." FWIW

My $0.02 on this. The Ramjet I saw on OEM calibration made something like 180 RWHP in a K1500. With a tuned 0411 and coil per cylinder ignition it made 224 RWHP Both setups were still using exhaust manifolds and full exhaust as opposed to 1 3/4" primary long tubes and 3" open pipes in a dyno cell running without accessories. Remove the trick dyno exhaust for something street legal and add accessory drag and you are suddenly down 40-50 HP from the inflated dyno run.
That being said drivetrain loss of a 4L85E and 9.5" 14-bolt is about 25%. I was able to get to 250 RWHP on gasoline. On E85 it was 272 rwhp. 272/.75 = 362.6 hp. The marine intake also does not breath the same way the Ramjet manifold does but makes more torque because of its longer runners. For reference a 340 HP 8.1 puts down about 240 RWHP with the same driveline.

Truth be known a flat top piston would probably have made the engine less knock prone than the crappy stock dish pistons because of the added quench benefit.

FWIW the old version of the Ramjet when it still had 1.6 rocker was rated at 351 HP and 401 TQ.

 

[c1500deathtrap]

So, I have been talked out of buying the LT1 for my 1996 Chevy truck. I am glad I was after reading your threads. Now I am considering going with a reman long block 350. Since I live in NC I have to stay with a 1996-1999 engine for emissions laws here. So, with that said, If I go ahead with the long block 350, what would be a good cam to have installed? I have to use the spider injection senerio , that could be modified I hope, to get a few extra HP out of the L31 ? I already have a set of BBK shorty headers and a 3" Magnaflow exhaust to finish the exhaust up. Another question is, I have 3.42 gears in the rear end I believe, should I change those out as well?

Again many thanks for your advice,Dan

psst It's not illegal to swap a newer emissions compliant setup into an older vehicle, i.e 5.3 swap (Provided it passes emissions testing)
https://www.epa.gov/sites/production/files/documents/engswitch_0.pdf
https://www.afdc.energy.gov/pdfs/2753.pdf
Also where in NC do you live that is that ****?

 

[454cid]

That being said drivetrain loss of a 4L85E and 9.5" 14-bolt is about 25%. I was able to get to 250 RWHP on gasoline. On E85 it was 272 rwhp. 272/.75 = 362.6 hp. The marine intake also does not breath the same way the Ramjet manifold does but makes more torque because of its longer runners. For reference a 340 HP 8.1 puts down about 240 RWHP with the same driveline.

Are you talking about a swapped 8.1L? I'm not aware of the 8.1 getting any less than a 14BFF rear axle...and I think they usually got the 11.5"

 

[L31MaxExpress]

Are you talking about a swapped 8.1L? I'm not aware of the 8.1 getting any less than a 14BFF rear axle...and I think they usually got the 11.5"

Had 9.5" on the mind but meant 10.5". When I ran that dyno it was on the 8 lug rear-end not the 6 lug. I have had an 8.5, 9.5 and 10.5 in the Express. I thought the 11.5 was used in Duramax trucks. The Avalanche/Suburban are 3/4 tons and should have 10.5s.

 

[89GMCJOHN]

L31 writes "The Ramjet I saw on OEM calibration made something like 180 RWHP in a K1500."

Compared to HOT ROD MAGAZINES dyno cell test of the RamJet 364 hp at 5,000 and 413 lb-ft at 4,100 rpm.

So you are saying a Ramjet loses 184 hp on the dyno rollers. That would be a 50% reduction in rated power ..not the traditional 25% dyno loss as is commonly stated everywhere out there. Interesting .

I think your math is wrong "On E85 it was 272 rwhp. 272/.75 = 362.6 hp"

I think you meant to say 272 rwhp *1.25 = 340 hp not 362 ........ you had better heads / 2.02 valves , upgraded springs and your custom tuning skills. Are Chevrolet AND Hot Rod lying ? Stock ramjet still made more power .

 

[L31MaxExpress]

L31 writes "The Ramjet I saw on OEM calibration made something like 180 RWHP in a K1500."

Compared to hot rods dyno cell test of the RamJet 364 hp at 5,000 and 413 lb-ft at 4,100 rpm.

So you are saying a Ramjet loses 184 hp on the dyno rollers. That would be a 50% reduction in rated power ..not the traditional 25% dyno loss as is commonly stated everywhere out there. Interesting .

I think your math is wrong "On E85 it was 272 rwhp. 272/.75 = 362.6 hp"

I think you meant to say 272 rwhp *1.25 = 340 hp not 362 ........ you had better heads / 2.02 valves , upgraded springs and your custom tuning skills. Are Chevrolet AND Hot Rod lying ? Stock ramjet still made more power .

Your math is wrong, let me show you, as it does not work the way you expressed it.

Your way
100 x .75 = 75 * 1.25 = 93.75

My way
100 x .75 = 75 /.75 = 100

Chevrolet is not wrong and neither is Hot Rod, they are just not running the engine with any accessories. Accessories are not included in drivetrain loss. Drivetrain loses a percentage of power but so do the accessories. With a full complement of accessories that power loss can add up to 20-30 hp. Clutch fan alone can eat 8-10 HP. Alternator 2-3 HP. Water pump up to ~10 HP. Also factor in the the dyno exhaust system probably added 25-30 HP on its own over what most 4x4 trucks can use for an exhaust which also effects the MEFI4s calibration on the Ramjet by running much richer than necessary. So before you even hook a driveline to the engine, the engine is already down 40-60 HP from what it put down in a dyno cell without accessories.

FWIW NYC Performance Tuning (said Wester's garage at first) ran a 1995 Yukon on the dyno with a Ramjet 350 and only made 212 RWHP and 265 RWTQ AFTER tuning!

You must be registered for see images attach

You can also clearly see how HotRod tested this engine. Look at those nice tuned length racing headers with what looks to be 1 3/4" primaries, 3" flowmasters with no exhaust tubing or bends, no air cleaner or intake ducting, electric water pump, no other accessories, etc.

You must be registered for see images attach

 

[89GMCJOHN]

You originally said a k1500 with ramjet put down 180 hp which was our starting point here for this discussion .....now you are saying a Yukon with Ramjet put down 212 ,,,thats a big 32 hp difference - so make your mind up on the starting hp figure for a ramjet you are finally discussing. At your original statement of 180 hp multiply that by 1.25 (dyno losses added back in ) and you get 225 hp , So are you still stating accessories, intake difference and exhaust are eating up an additional 139 hp on that ramjet setup ? Recall Hotrod says it had 364 hp. Somethings obviously wrong with that setup you had with its pinging etc . These old engines on the dyno rollers probably have carbon buildup on top of the valves , plugged converters,less than optimal tunes,plugs, wires etc more than likely .

This whole discussion boils down to its a tiny cam that dyno cells at a respectable 364 hp 413 tq. Yes it noses over at 4700-5k, Why would you even throw 2.02s , 1.7s , better springs and countless tunes on a tiny 246 duration cam and expect any big improvements then tell everyone its a dog.

 

[L31MaxExpress]

You originally said a k1500 with ramjet put down 180 hp which was our starting point here for this discussion .....now you are saying a Yukon with Ramjet put down 212 ,,,thats a big 32 hp difference - so make your mind up on the starting hp figure for a ramjet you are finally discussing. At your original statement of 180 hp multiply that by 1.25 (dyno losses added back in ) and you get 225 hp , So are you still stating accessories, intake difference and exhaust are eating up an additional 139 hp on that ramjet setup ? Recall Hotrod says it had 364 hp. Somethings obviously wrong with that setup you had with its pinging etc .

This whole discussion boils down to its a tiny cam that dyno cells at a respectable 364 hp 413 tq. Yes it noses over at 4700-5k, Why would you even throw 2.02s , 1.7s , better springs and countless tunes on a tiny 246 duration cam and expect any big improvements then tell everyone its a dog.

The 175 HP K1500 was a thread on Pacific audio by S10Wildside who helps co run EFI Connection. The stock MEFI4 calibration literally made 175 RWHP. The tuned 0411/24x swap made 224 rwhp after tuning. Dyno sheet was no longer a good link so I found a second very similar result via google.

Detonation in my situation was from lack of octane for the DCR used in my application, PERIOD. More octane and cooler burning fuel aka E85 resulted in more HP/TQ as a result of being able to increase timing to MBT that was not octane limited to a lower timing advance curve. The engine responded to 6-10° more timing in places on 104 octane E85 where it would have knocked its ass off on 93.

That being said you would expect 2.02/1.60s and 1.7 rockers to perform better regardless of the cam choice. I pull a 6K travel tailer with a 6,200 lbs Express often. I like having power to accelerate when I need to and climb hills in 2nd gear as needed at highway speeds.

You are still doing the math wrong. Divide by .75 to convert RWHP to FWHP as I proved in the math above.

I threw springs on it because it had obvious valve float and I had intentions for a future cam swap again anyway.

 

[89GMCJOHN]

I'm done and done trying to explain …. nobody is down 170 hp from accessories,exhaust,intake on a new ramjet 350 period something's wrong with that setup too in your latest example ...SIMPLY Chevrolet sells them with the advertised HP and TQ slightly underrated to avoid lawsuits . those motors you cite had obvious issues i.e. old, carboned up, plugged catalytic converter, tune , plugs ? Etc.....it's a tiny camshaft with 400 ft lbs is all I need to know when its brand new ,I drive the cam now ,I have built a couple and both ran fine, it's not a dog. I'm not 6200 lbs,I have no pinging and I am not drag racing a van.

 

[c1500deathtrap]

Holy **** where is OP? Can we get this thread back on track?