To much HP?
Thread Starter
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
Race Director
Joined: May 2003
Posts: 11,814
Likes: 9
From: Science Bitch! Mississauga, Ontario
Canadian Events Coordinator
Burning Brakes
Joined: May 2009
Posts: 850
Likes: 36
From: Providence RI
It's not just about how much hp you have, it's about *where* you have that hp.
Unfortunately, some setups may make higher hp figures at higher engine rpms, but also make lower hp at lower rpms. You have to compensate by changing the gear-ratio and installing a looser converter so that the engine is in its optimal rpm range, but this is not always that fun on the street.
The primary thing you'll want is to identify the rpm range you are most comfortable for your ordinary driving, and choose an engine-combination that maximizes power in that range. You might find that a 300hp engine that makes that power at 4000rpm is a lot more enjoyable than a 500hp engine that makes that power at 7000rpm, but that only makes 200hp from 2000rpm-4000rpm.
Unfortunately, some setups may make higher hp figures at higher engine rpms, but also make lower hp at lower rpms. You have to compensate by changing the gear-ratio and installing a looser converter so that the engine is in its optimal rpm range, but this is not always that fun on the street.
The primary thing you'll want is to identify the rpm range you are most comfortable for your ordinary driving, and choose an engine-combination that maximizes power in that range. You might find that a 300hp engine that makes that power at 4000rpm is a lot more enjoyable than a 500hp engine that makes that power at 7000rpm, but that only makes 200hp from 2000rpm-4000rpm.
Thread Starter
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
It's not just about how much hp you have, it's about *where* you have that hp.
Unfortunately, some setups may make higher hp figures at higher engine rpms, but also make lower hp at lower rpms. You have to compensate by changing the gear-ratio and installing a looser converter so that the engine is in its optimal rpm range, but this is not always that fun on the street.
The primary thing you'll want is to identify the rpm range you are most comfortable for your ordinary driving, and choose an engine-combination that maximizes power in that range. You might find that a 300hp engine that makes that power at 4000rpm is a lot more enjoyable than a 500hp engine that makes that power at 7000rpm, but that only makes 200hp from 2000rpm-4000rpm.
Unfortunately, some setups may make higher hp figures at higher engine rpms, but also make lower hp at lower rpms. You have to compensate by changing the gear-ratio and installing a looser converter so that the engine is in its optimal rpm range, but this is not always that fun on the street.
The primary thing you'll want is to identify the rpm range you are most comfortable for your ordinary driving, and choose an engine-combination that maximizes power in that range. You might find that a 300hp engine that makes that power at 4000rpm is a lot more enjoyable than a 500hp engine that makes that power at 7000rpm, but that only makes 200hp from 2000rpm-4000rpm.
Instructor
Joined: Aug 2010
Posts: 249
Likes: 4
From: Eastern Ky
No problem. Had it for about 8 years. One note: The origional paperwork that came with the engine recommended a 750 carb. The engine drowned with that carb. Never could get it adjusted out until I went with a 600. Now I hear the recommendation is for a 600 - 650 CFM carb.
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Thread Starter
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
No problem. Had it for about 8 years. One note: The origional paperwork that came with the engine recommended a 750 carb. The engine drowned with that carb. Never could get it adjusted out until I went with a 600. Now I hear the recommendation is for a 600 - 650 CFM carb.
Thread Starter
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
I have to split time because I have a bike and I really like to ride.
Racer
Joined: Jul 2011
Posts: 265
Likes: 77
From: chicagoland il
In the process of having my l48 replaced with a 434 sbc or 383 sbc. With the 434 build, we are shooting for around 518 hp/ 550tq. The car will be very streetable/docile on pump gas and still get mid-upper teen mpg.
What we decided was to keep the stock th350 and 308 rear end. Not having to rebuild the driveline and put the money saved into the engine. This would make the car streetable with reasonable rpm at cruising. The trick will be to build an engine that is tuned to the th350/308 rear end. This would mean maxing tq at around 3500rpm with a 22-2400 stall.
Just by nature, the 400sbc has significant tq. the large hp/tq numbers are just a by product of of the build with good flowing heads. Much emphasis would be in matching cam/compression/rod ratio etc. to achieve the results.
Crate engines may be a convenient one stop shop, but not tuned to your specific rear end gearing.
What we decided was to keep the stock th350 and 308 rear end. Not having to rebuild the driveline and put the money saved into the engine. This would make the car streetable with reasonable rpm at cruising. The trick will be to build an engine that is tuned to the th350/308 rear end. This would mean maxing tq at around 3500rpm with a 22-2400 stall.
Just by nature, the 400sbc has significant tq. the large hp/tq numbers are just a by product of of the build with good flowing heads. Much emphasis would be in matching cam/compression/rod ratio etc. to achieve the results.
Crate engines may be a convenient one stop shop, but not tuned to your specific rear end gearing.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
In the process of having my l48 replaced with a 434 sbc or 383 sbc. With the 434 build, we are shooting for around 518 hp/ 550tq. The car will be very streetable/docile on pump gas and still get mid-upper teen mpg.
What we decided was to keep the stock th350 and 308 rear end. Not having to rebuild the driveline and put the money saved into the engine. This would make the car streetable with reasonable rpm at cruising. The trick will be to build an engine that is tuned to the th350/308 rear end. This would mean maxing tq at around 3500rpm with a 22-2400 stall.
Just by nature, the 400sbc has significant tq. the large hp/tq numbers are just a by product of of the build with good flowing heads. Much emphasis would be in matching cam/compression/rod ratio etc. to achieve the results.
Crate engines may be a convenient one stop shop, but not tuned to your specific rear end gearing.
What we decided was to keep the stock th350 and 308 rear end. Not having to rebuild the driveline and put the money saved into the engine. This would make the car streetable with reasonable rpm at cruising. The trick will be to build an engine that is tuned to the th350/308 rear end. This would mean maxing tq at around 3500rpm with a 22-2400 stall.
Just by nature, the 400sbc has significant tq. the large hp/tq numbers are just a by product of of the build with good flowing heads. Much emphasis would be in matching cam/compression/rod ratio etc. to achieve the results.
Crate engines may be a convenient one stop shop, but not tuned to your specific rear end gearing.
Keep the shiny side up!
Scott
Advanced
Joined: Aug 2011
Posts: 98
Likes: 0
From: MA
didnt these cars have at tops about 250 for the small blocks pre 1973 and about 330 for the big blocks like the 454 with a ton of torque?
I mean wouldnt it be easier to just have an engine rebuild and then put some new stuff on it like a higher performance cam shaft and all those goodies before doing something drastic, or just do that from the getgo and skip the engine rebuild bit.
I mean wouldnt it be easier to just have an engine rebuild and then put some new stuff on it like a higher performance cam shaft and all those goodies before doing something drastic, or just do that from the getgo and skip the engine rebuild bit.
Racer
Joined: Jul 2011
Posts: 265
Likes: 77
From: chicagoland il
You are going to put that much time, effort, and money into an engine like that, and chintz out on the tranny? My Grandpappy would have told you "Son, I say, I say, son, you're a penny wise, but a dollar foolish!". (I threw the Foghorn Legorn bit in there for the humorous effect, my Grandpappy didn't really talk that way.) A modern overdrive transmission has soooo many advantages over an old 3-speed, it's no comparison. The deeper first gear, the overdrive, lock up converter, c'mon, man! Think about it. Ahhhh, you can always do it later, I guess.
Keep the shiny side up!
Scott
Keep the shiny side up!
Scott
Thread Starter
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
didnt these cars have at tops about 250 for the small blocks pre 1973 and about 330 for the big blocks like the 454 with a ton of torque?
I mean wouldnt it be easier to just have an engine rebuild and then put some new stuff on it like a higher performance cam shaft and all those goodies before doing something drastic, or just do that from the getgo and skip the engine rebuild bit.
I mean wouldnt it be easier to just have an engine rebuild and then put some new stuff on it like a higher performance cam shaft and all those goodies before doing something drastic, or just do that from the getgo and skip the engine rebuild bit.
I have been researching machine shops in my area.
I talked to my dad (insane mechanic) this weekend and he gave 2 points. Go crate if I want a quick turn around. Or take the same amount of money and do the rebuild with some moderate upgrades to achieve what I am looking for. He was more in favor of the rebuild.
Again, thanks for all the input, please keep them coming. There have been some really good points and tech tips put up here, that I would have never thought of. I will use this info to help make my decision, This winter is when I want to do this project. T
Thanks guys.
