454 merc build recommendations
09-20-2023, 01:22 PM
#31
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Thread Starter
Hmm not sure how to tell what kind of engine I have from that
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F-2 Speedy (09-20-2023)
09-20-2023, 01:36 PM
#33
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09-20-2023, 01:41 PM
#34
Remember, we're talking about a stock/factory Merc 454cid/330hp engine and how to modify it from its original stock/factory build form while retaining most of the parts from the same engine. This is basically a LOW BUDGET UPGRADE that will work/survive within certain parameters---that's basically why we called it a "Merc 330hp on steroids" It's for the guy who would like a little more power without breaking the bank or his wallet while basically using the Merc 330hp engine as a base platform.
From what I can remember from back in the day (early 1980's) guys looking to get 400-475hp from the 330hp engine was what they wanted and my friend's 1978 30' Scarab had a pair of Merc 454"/330hp engines in his boat back then with the old Merc heavy, crude, cast iron "log" style 2.5-3" exhaust manifolds.
The legendary Ray Baker and his engine building shop (Baker Engineering) I lived close by just outside of Grand Rapids, Michigan... I would see him at some of the Offshore boat racing events in Grand Haven in the tent areas near the pits---I specifically discussing the Merc 454"/330hp engine and he told me he had dyno tested some factory new Merc ones that he said usually made way less than even 300hp---like anywhere as low as 240-280hp (and I remember Ray saying "some even lower than that") with Merc's cast iron junk exhaust manifolds.
That was back in the mid 1980's or so and cannot remember all the small details but Ray's dyno tests revealed HP figures shockingly way below the adverstised "330hp" from the factory I remember thinking no wonder people wanted more power from the pitiful Merc so called "330hp"...and Ray was beginning to sell a lot of upgrade packages for the Merc 330's to customers back then.
Ray also told me that those Merc engines really needed a better breathing exhaust system just to wake them up much beyond 375hp. The first thing my friend did (with his 30' Scarab) was bought some used Hardin Marine P-1000 exhaust manifolds with dry tailpipes. Just by adding those alone woke his bone STOCK Merc 330's up from about 4200rpm before,---- all the way uo to 5000rpm afterwards.
If you are looking to approach the 400hp mark with a 454cid engine, then you have to begin looking at an aftermarket free breathing exhaust system and a DRY system where the discharge water does NOT mix anywhere within the collector/tailpipe, then the more and better potential for making power. Anyway, that was our starting point.
From what I can remember from back in the day (early 1980's) guys looking to get 400-475hp from the 330hp engine was what they wanted and my friend's 1978 30' Scarab had a pair of Merc 454"/330hp engines in his boat back then with the old Merc heavy, crude, cast iron "log" style 2.5-3" exhaust manifolds.
The legendary Ray Baker and his engine building shop (Baker Engineering) I lived close by just outside of Grand Rapids, Michigan... I would see him at some of the Offshore boat racing events in Grand Haven in the tent areas near the pits---I specifically discussing the Merc 454"/330hp engine and he told me he had dyno tested some factory new Merc ones that he said usually made way less than even 300hp---like anywhere as low as 240-280hp (and I remember Ray saying "some even lower than that") with Merc's cast iron junk exhaust manifolds.
That was back in the mid 1980's or so and cannot remember all the small details but Ray's dyno tests revealed HP figures shockingly way below the adverstised "330hp" from the factory I remember thinking no wonder people wanted more power from the pitiful Merc so called "330hp"...and Ray was beginning to sell a lot of upgrade packages for the Merc 330's to customers back then.
Ray also told me that those Merc engines really needed a better breathing exhaust system just to wake them up much beyond 375hp. The first thing my friend did (with his 30' Scarab) was bought some used Hardin Marine P-1000 exhaust manifolds with dry tailpipes. Just by adding those alone woke his bone STOCK Merc 330's up from about 4200rpm before,---- all the way uo to 5000rpm afterwards.
If you are looking to approach the 400hp mark with a 454cid engine, then you have to begin looking at an aftermarket free breathing exhaust system and a DRY system where the discharge water does NOT mix anywhere within the collector/tailpipe, then the more and better potential for making power. Anyway, that was our starting point.
Last edited by KAAMA; 09-20-2023 at 01:44 PM.
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1983ScarabIII (09-20-2023)
09-20-2023, 02:01 PM
#35
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09-20-2023, 02:49 PM
#36
You will hear 101 different opinions on here including my own.... and I am not saying my opinion is the right one either. I'm just giving you some testimony on what I have witnessed and expeienced over the many years when the Merc 454"/330hp engine was what guys wanted to upgrade way back then. Technology has certainly come a long way since the 1980's...with tons of more parts options, etc...so yes, you can go out and lay down the smack for a new 502 crate engine or other options.
The thing you will want and need to make sure of is, accurate machining process---even on a new factory crate that was/is not designed for marine usage especially when it comes to all the bearing, valve guide, piston/ring clearances, etc. .... unless you trust the factory. Because you would have to have all that stuff checked out and properly clearanced if you rebuild your 454"/330hp engine===or any engine destined for marine hi-perf use.....even a new from the factory crate engine would still be a wise thing to do.
Perhaps a factory crate engine would be a better choice these days if you have the money--- but you are the one who has to determine all the machine work costs and other costs involved, but you were specifically asking about the engine you currently have now. It's your money and your decision. You have to weigh it all out and do your own due diligence.
I will post again later of what we had to do with the 454'/330hp engines we had back in the early 1980's and others that I have seen built back in those days... we did not have the options that we have these days.
The thing you will want and need to make sure of is, accurate machining process---even on a new factory crate that was/is not designed for marine usage especially when it comes to all the bearing, valve guide, piston/ring clearances, etc. .... unless you trust the factory. Because you would have to have all that stuff checked out and properly clearanced if you rebuild your 454"/330hp engine===or any engine destined for marine hi-perf use.....even a new from the factory crate engine would still be a wise thing to do.
Perhaps a factory crate engine would be a better choice these days if you have the money--- but you are the one who has to determine all the machine work costs and other costs involved, but you were specifically asking about the engine you currently have now. It's your money and your decision. You have to weigh it all out and do your own due diligence.
I will post again later of what we had to do with the 454'/330hp engines we had back in the early 1980's and others that I have seen built back in those days... we did not have the options that we have these days.
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1983ScarabIII (09-20-2023)
09-20-2023, 04:01 PM
#37
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Remember, we're talking about a stock/factory Merc 454cid/330hp engine and how to modify it from its original stock/factory build form while retaining most of the parts from the same engine. This is basically a LOW BUDGET UPGRADE that will work/survive within certain parameters---that's basically why we called it a "Merc 330hp on steroids" It's for the guy who would like a little more power without breaking the bank or his wallet while basically using the Merc 330hp engine as a base platform.
From what I can remember from back in the day (early 1980's) guys looking to get 400-475hp from the 330hp engine was what they wanted and my friend's 1978 30' Scarab had a pair of Merc 454"/330hp engines in his boat back then with the old Merc heavy, crude, cast iron "log" style 2.5-3" exhaust manifolds.
The legendary Ray Baker and his engine building shop (Baker Engineering) I lived close by just outside of Grand Rapids, Michigan... I would see him at some of the Offshore boat racing events in Grand Haven in the tent areas near the pits---I specifically discussing the Merc 454"/330hp engine and he told me he had dyno tested some factory new Merc ones that he said usually made way less than even 300hp---like anywhere as low as 240-280hp (and I remember Ray saying "some even lower than that") with Merc's cast iron junk exhaust manifolds.
That was back in the mid 1980's or so and cannot remember all the small details but Ray's dyno tests revealed HP figures shockingly way below the adverstised "330hp" from the factory I remember thinking no wonder people wanted more power from the pitiful Merc so called "330hp"...and Ray was beginning to sell a lot of upgrade packages for the Merc 330's to customers back then.
Ray also told me that those Merc engines really needed a better breathing exhaust system just to wake them up much beyond 375hp. The first thing my friend did (with his 30' Scarab) was bought some used Hardin Marine P-1000 exhaust manifolds with dry tailpipes. Just by adding those alone woke his bone STOCK Merc 330's up from about 4200rpm before,---- all the way uo to 5000rpm afterwards.
If you are looking to approach the 400hp mark with a 454cid engine, then you have to begin looking at an aftermarket free breathing exhaust system and a DRY system where the discharge water does NOT mix anywhere within the collector/tailpipe, then the more and better potential for making power. Anyway, that was our starting point.
From what I can remember from back in the day (early 1980's) guys looking to get 400-475hp from the 330hp engine was what they wanted and my friend's 1978 30' Scarab had a pair of Merc 454"/330hp engines in his boat back then with the old Merc heavy, crude, cast iron "log" style 2.5-3" exhaust manifolds.
The legendary Ray Baker and his engine building shop (Baker Engineering) I lived close by just outside of Grand Rapids, Michigan... I would see him at some of the Offshore boat racing events in Grand Haven in the tent areas near the pits---I specifically discussing the Merc 454"/330hp engine and he told me he had dyno tested some factory new Merc ones that he said usually made way less than even 300hp---like anywhere as low as 240-280hp (and I remember Ray saying "some even lower than that") with Merc's cast iron junk exhaust manifolds.
That was back in the mid 1980's or so and cannot remember all the small details but Ray's dyno tests revealed HP figures shockingly way below the adverstised "330hp" from the factory I remember thinking no wonder people wanted more power from the pitiful Merc so called "330hp"...and Ray was beginning to sell a lot of upgrade packages for the Merc 330's to customers back then.
Ray also told me that those Merc engines really needed a better breathing exhaust system just to wake them up much beyond 375hp. The first thing my friend did (with his 30' Scarab) was bought some used Hardin Marine P-1000 exhaust manifolds with dry tailpipes. Just by adding those alone woke his bone STOCK Merc 330's up from about 4200rpm before,---- all the way uo to 5000rpm afterwards.
If you are looking to approach the 400hp mark with a 454cid engine, then you have to begin looking at an aftermarket free breathing exhaust system and a DRY system where the discharge water does NOT mix anywhere within the collector/tailpipe, then the more and better potential for making power. Anyway, that was our starting point.
What is your opinion on the dry exhaust 1/8" weep holes at the tips of the pipes to cool the mufflers?
One of the issues I've seen on my dry to tip system is the pipe outlets discharge inside the hull...plumbed to the transom dedicated water outlet. All great, except the last 15" of pipe has no water flow for cooling without the weep holes...even without clamp on mufflers.
800 rpm on the top end is a massive airflow increase with no other changes. Best money spent on good exhaust.
Wasn't there some info and threads that good open but short style exh manifolds performed just as well or better than full length tube style?
09-20-2023, 04:09 PM
#38
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Thread Starter
I thought of getting a crate engine as well, but since I'm getting the labor for free (except bore and hone which seems to be around 500-800 USD) that just seems like a way more expensive option. The cheapest 502 I can seem to find is about 10k and then I would still have to get an exhaust on top of that. Of course I get some money from selling my old engine but in order to sell that with a good conscience I would still need rebuild it since it's consuming oil. Unless I'm missing something.
The only advantage I can see with a 502 crate is that it's more susceptible to future upgrades. But I think if I'm ever going to go beyond this build I'd replace the hull as well with a more proven hull and I suppose it's easier to sell the whole boat as is and get a whole boat with engine. Is this train of thought wrong?
The only advantage I can see with a 502 crate is that it's more susceptible to future upgrades. But I think if I'm ever going to go beyond this build I'd replace the hull as well with a more proven hull and I suppose it's easier to sell the whole boat as is and get a whole boat with engine. Is this train of thought wrong?
09-20-2023, 06:52 PM
#39
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I thought of getting a crate engine as well, but since I'm getting the labor for free (except bore and hone which seems to be around 500-800 USD) that just seems like a way more expensive option. The cheapest 502 I can seem to find is about 10k and then I would still have to get an exhaust on top of that. Of course I get some money from selling my old engine but in order to sell that with a good conscience I would still need rebuild it since it's consuming oil. Unless I'm missing something.
The only advantage I can see with a 502 crate is that it's more susceptible to future upgrades. But I think if I'm ever going to go beyond this build I'd replace the hull as well with a more proven hull and I suppose it's easier to sell the whole boat as is and get a whole boat with engine. Is this train of thought wrong?
The only advantage I can see with a 502 crate is that it's more susceptible to future upgrades. But I think if I'm ever going to go beyond this build I'd replace the hull as well with a more proven hull and I suppose it's easier to sell the whole boat as is and get a whole boat with engine. Is this train of thought wrong?
As many can attest here on OSO...if you build up a good engine with exhaust etc...you likely won't get the money out of it when you sell it.
A quart/hr oil consumption is pretty rough. Intake gasket leak? Rings would have to be rough for that level of use. Compression test and or leakdown test would give you a lot of info.
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1983ScarabIII (09-21-2023)
09-20-2023, 10:29 PM
#40
Kaama,
What is your opinion on the dry exhaust 1/8" weep holes at the tips of the pipes to cool the mufflers?
800 rpm on the top end is a massive airflow increase with no other changes. Best money spent on good exhaust.
Wasn't there some info and threads that good open but short style exh manifolds performed just as well or better than full length tube style?
What is your opinion on the dry exhaust 1/8" weep holes at the tips of the pipes to cool the mufflers?
800 rpm on the top end is a massive airflow increase with no other changes. Best money spent on good exhaust.
Wasn't there some info and threads that good open but short style exh manifolds performed just as well or better than full length tube style?
Anyway Tart, I highly doubt a 1/8" weep hole would hurt performance as long as you're not dumping the entire water cooling charge into the tailpipe.
I should note on those P-1000 exhaust systems we had that the water dumped at the very tip on the inside of the jacketed tailpipe---2 holes at the top and 1-hole at the bottom---we latter installed a pair of Merc's 440hp cams on a 110* LSA (they were actually made by Ultradyne Cams), but we never experienced any water reversion with that P-1000 exhaust set-up.
Yeah, it was something like 4200-4400rpm (almost laughable on a boat like that these days) on my friend's 30' Scarab---so, adding those dry P-1000 exhaust manifolds really woke up those 330's...we already knew we would see an increase, but were very surprised with the RPM increase/difference.
Keep in mind, you don't need a full length tubular header exhaust system----those P-1000 exhausts were a jacketed aluminum Manifold design with dry jacketed stainless steel tailpipes that worked well enough for what we wanted to do back then at that time.
Try not too laugh, but back then we always thought we'd be "one of the boys" .if we could just make 440hp with our own home-made recipe on a budget 440hp engine as compared to Merc's 440hp engine. Mercs 454"/440hp engines came stock from Merc with GIL exhaust manifolds and stainless steel dry pipes back then as well---they were comparable to the P-1000's. Another manifold style exhaust system that would work well is a Stainless Marine system.
A good breathing exhaust system is going to take a good little chunk of the of the money out of the budget for a warm up on a 454"/330hp on steroids project though--- it's one of those things guys may tend to forget about when doing these kinds of upgrades. Anyway, back then we thought if we could make a true 440hp from our pitiful Merc 330's using the same 454cid from a stock factory Merc 330hp we would be very happy. We were just guys who barely had enough money to scrape up and be able to dump in these boats/engines back then.
Another thing I forgot to mention when talking to Ray Baker back in the mid-80's about the Merc 454"/330hp engine was that I remember him telling me that the best Merc 454"/330hp engine that he ever dyno tested only made 313hp---and it was new out of some guy's boat---but he said some of the better ones dyno'd at about only 280hp-----and usually much lower than that and I remember one of his employees telling me that too. .
I do NOT know exactly where to split the hair exactly when making power using various stock Merc cast iron crude breathing exhaust systems that you can try get away with to obtain a certain amount of horsepower. Merc used to produce the old 454"/370hp and the 454"/400hp engines back then and they only had the stock Merc cast iron heavy log style very crude breathing exhaust systems on them and I am sure they most likely did not make the advertised HP with those engines either---soon, one of the options Merc offered the GIL exhaust manifolds with stainless tailpipes with their 454"/400hp engines and I think they called it their 400hp Cyclone High Performance package---I am sure it made closer to the 400hp mark than the one's with the cast iron exhaust system ...,
.....but remember if you are on a budget with a 454cid or any engine with the old heavy cast iron exhaust system, then keep in mind the more power you want to make---then the more you will need to lean towards a good, aftermarket free breathing exhaust system.
Last edited by KAAMA; 09-20-2023 at 10:34 PM.
