Thread: hey all, quick engine question

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im building a porsche 914 with a chevy v8 and need some engine knowledge. i need to get close but not over 300hp and no more than 300tq since my trans is limited to that horse power and tq level. i would like the engine to rev and to make my max hp in the higher rpm i was thinking of using a custom built 283 or 302. what do you guys think.

.....I'm not trying to answer your question with ideas that your not interested in but; Why do you want something that rev's high up the RPM scale? The reason I ask is to get your HP up high means a big cam, which means high compression, which can play havoc on pump gas. RPM will hurt a motor more than HP which means you muct use top quality parts which means added exspence. Plus you need lower gears to keep it in the upper RPM's which means, more wear & tear on everything & worse gas milage. Is it a street car??? Road racer??? In my opinion Tq. is better on the street cuz it comes on lower on the RPM scale. This means if your crusing down the street at 2000 RPM & you want to take off like a rabbit you must put the clutch in, rev it to 5 grand & pop the clutch. With a low RPM motor you just punch it. Your transmission that is rated at 300 HP/300 TQ would live longer with a low RPM Tq motor. Now some people on the board will certainally disagree with me but I'd put a 350 crate motor in it. Go to SDPC2000.com & check out the crate motors. A 350 with 300 Tq. & 250 HP for $1400 {not counting intake, carb & ignition. Or a 350 w/ 330 HP & 380 Tq for $2400 {again, no carb, intake or ignition}. This puts the Tq out @ 3800 RPM. The trans would live forever. {disclaimer! do this at your own risk}..... But you get the idea. Some of the other folks can fill you in on high RPM motors but your money is going to be lots more, less dependable, worse gas milage, etc, etc, etc....... Again, not trying to tell you want you don't want to hear but this is just my opinion.... bill

Ps, I see you live in Orange County??? Well the Tq motor is also easier to drive in traffic & will run much cooler. So less money spent on your cooling system. Oh, crate motors have warrentees & with custom built high RPM motors you get the tail light warrentee. Meaning it's warrentted until I can't see your tail lights anymore...... Hope this helps ya.....

ive run a 350 chev through that transaxel , 4 gear is to small and the torque on it will cause it to fail, happened twice to me !
ive upgraded to a g50, problem solved.
you may want to consider a buick v6

You're going to have to have a really mild engine to keep from wounding the transaxle......even a 283 with enough goodies in it to make it rev high is probably going to exceed the torque rating of the transaxle and half shafts.......

You mean like a Corvette, or a Jag transaxle, or just the Porshe is too fragile???

Almost all sbc V-8's come stock near 300 hp, Modpr3. If you want a winder motor than find a 283, 307, 327, and have the heads done for unleaded fuel.
Good luck with your build.

yah you guys are all pretty much right, i have a 283 in my 914 and i am always worrying about the transaxle. tq. will rip it apart even 300lbs of tq is too much. this swap would make an unbeatable car if the transaxle would hold, you can put transaxles out of 911 in the car but that costs lots of $$ and isnt an easy swap b/c it requires flipping the ring and pinion

Originally posted by billlsbird
.....I'm not trying to answer your question with ideas that your not interested in but; Why do you want something that rev's high up the RPM scale? The reason I ask is to get your HP up high means a big cam, which means high compression, which can play havoc on pump gas. RPM will hurt a motor more than HP which means you muct use top quality parts which means added exspence. Plus you need lower gears to keep it in the upper RPM's which means, more wear & tear on everything & worse gas milage. Is it a street car??? Road racer??? In my opinion Tq. is better on the street cuz it comes on lower on the RPM scale. This means if your crusing down the street at 2000 RPM & you want to take off like a rabbit you must put the clutch in, rev it to 5 grand & pop the clutch. With a low RPM motor you just punch it. Your transmission that is rated at 300 HP/300 TQ would live longer with a low RPM Tq motor. Now some people on the board will certainally disagree with me but I'd put a 350 crate motor in it. Go to SDPC2000.com & check out the crate motors. A 350 with 300 Tq. & 250 HP for $1400 {not counting intake, carb & ignition. Or a 350 w/ 330 HP & 380 Tq for $2400 {again, no carb, intake or ignition}. This puts the Tq out @ 3800 RPM. The trans would live forever. {disclaimer! do this at your own risk}..... But you get the idea. Some of the other folks can fill you in on high RPM motors but your money is going to be lots more, less dependable, worse gas milage, etc, etc, etc....... Again, not trying to tell you want you don't want to hear but this is just my opinion.... bill

Ps, I see you live in Orange County??? Well the Tq motor is also easier to drive in traffic & will run much cooler. So less money spent on your cooling system. Oh, crate motors have warrentees & with custom built high RPM motors you get the tail light warrentee. Meaning it's warrentted until I can't see your tail lights anymore...... Hope this helps ya.....

hey no, i appriciate the ideas thats what im looking for. i feel stupid since i thought if you have a motor that puts most of the power ant torque at high rpms you could stay at low rpms driving around town and not use up that much gas, granted thought with a high comp. engine i will have to use 91 octane instead of 87. but you brought up that i would have to rev the engine and drop the clutch my trans definitely wouldnt like that.

Originally posted by ratsass
ive run a 350 chev through that transaxel , 4 gear is to small and the torque on it will cause it to fail, happened twice to me !
ive upgraded to a g50, problem solved.
you may want to consider a buick v6

an all aluminum v6 would be sweet but they say it causes to much vibration in the car. since the cars so small. my car probably weighs in at 2000lbs.

I'd look into a Pontiac GrandPrix GTP motor... supercharged 3.8L

Originally posted by BigEasy
I'd look into a Pontiac GrandPrix GTP motor... supercharged 3.8L

......yeah, one 3.8 supercharged V-6 {with an iron block & iron heads} that I read about puts out 260 Hp & 280 Tq. and the other 240 HP & 280 Tq.... That would be sweet.....

i picked up a SC 1998 3.8 from a grand prix for my dune buggie havent tried it yet but the price for hp is exellent!!!!!!

Originally posted by modpr3
hey no, i appriciate the ideas thats what im looking for. i feel stupid since i thought if you have a motor that puts most of the power ant torque at high rpms you could stay at low rpms driving around town and not use up that much gas, granted thought with a high comp. engine i will have to use 91 octane instead of 87. but you brought up that i would have to rev the engine and drop the clutch my trans definitely wouldnt like that.

Hey Modpr3, Don't ever feel stupid thinking about doing anything.
That's a good way to learn. Think about doing something and then ask questions...... Now on the other hand, when you thing about doing something, ask questions about it, people advise you not to do it & you do it anyway? Now that's STUPID..... bill

Originally posted by billlsbird
Hey Modpr3, Don't ever feel stupid thinking about doing anything.
That's a good way to learn. Think about doing something and then ask questions...... Now on the other hand, when you thing about doing something, ask questions about it, people advise you not to do it & you do it anyway? Now that's STUPID..... bill

hey thanks bill for the advice i really appriciate it, and same to the rest of you. im want to learn as much as i can not only about small block chevys but anything automotive.

im really thinking about that 350 crate motor you talked about. do you think the block is upgradeable. i saw it has four bolt mains. that engine might be a great setup for me to use right now with my current trans then if i want to save up and get the 930 trans (which can hold over 700hp) will i have a good block to build off of.

oh yeah and what kind of gas milalige do you think i would get with that crate engine.

thanks again
pat

Originally posted by hambiskit
You mean like a Corvette, or a Jag transaxle, or just the Porshe is too fragile???

Almost all sbc V-8's come stock near 300 hp, Modpr3. If you want a winder motor than find a 283, 307, 327, and have the heads done for unleaded fuel.
Good luck with your build.

I wish my old 77 Camaro with a 305 had near 300 h.p .I think it had less than 200 h.p..

Originally posted by modpr3
hey thanks bill for the advice i really appriciate it, and same to the rest of you. im want to learn as much as i can not only about small block chevys but anything automotive.

im really thinking about that 350 crate motor you talked about. do you think the block is upgradeable. i saw it has four bolt mains. that engine might be a great setup for me to use right now with my current trans then if i want to save up and get the 930 trans (which can hold over 700hp) will i have a good block to build off of.

oh yeah and what kind of gas milalige do you think i would get with that crate engine.

thanks again
pat

.....you could get that engine for now & then build off of it or what I would do is; use that engine for now & then sell it and get another crate motor later. Now I keep mentioning 'crate motors', thats because I never have & probably never will build my own motor. If you have the desire to build your own motors, go for it, I think it's a great idea. But I'm to old to start any more projects that I never finish. I'm putting a crate motor in the '32 that I'm having built, cuz 8 years ago I bought a '29 ford fiberglass roadster to build. I already have a narrowed 9" rear end, a turbo 400 transmission, & a 400 Chev motor for it. All this has been sitting for 8 years & I'm 58 years old. If I learn how to build motors now, I'll be dead before I get to drive my '32.... But enough about Bill, so back to modpr3. I'd say that you could build off of that block. But it'd be less down time If you just pulled your small 350 crate motor out and put a higher HP small block in. Cuz you'll already be set up for everything. So have another motor ready to put in right after you do a tranaxle swap. The transaxle swap is probably already a lot of work. Don't start more of a project than your going to finish {like I always do}. Your 714 sure would be something with an LS 6 crate motor in it {$7300}. Or buy the time you do this LS7 crate motors will be cheaper 505 HP {the new Vette engine}...... I don't know that much about gas milage. Go to www.sallee-chevrolet.com, they have a question/answer site where you ask quesions & a teck {or sales guy} answers them. They also sell crate motors like Smoggin Dickey Chev does {sdpc2000.com}. i would imagine that the gas milage is pretty good. The LS 6 motor that I mentioned about probably gets 20/28 or so..... Fuel injection gets better gas milage.... Also after you upgrade your transaxle your going to be dealing with; how much HP is prctical for the street. 700 HP in a 2300 pound car would be a handful to say the least. It'd be dangerours. Probably more than you'd even want.... {well, not want, but; more than you'd NEED ..... bill