snake70

hey guys i came across a weird looking mercusier marine intake manifold very rare like less then 500 produced between 87-89, i want to swap this on to my 400 sbc but it has a few issues there is no fuel pressure regulator and it uses a tps sensor that was supoably custom to the intake and lastly the the throttle cable hook ups are on the other side of the throttlebody, pics are comming tommarrow

TTOP350

iTrader: (8)

Its most likely the big block intake. It wont fit on a smallblock...

BuzzLOL

.. I read something yesterday about the 1996 Gen. 1 SBC Vortec engine, discontinued by GM about 2002, still being produced by Mercruiser for marine usage in the RamJet 350HO 350" configuration... also remember the 300HP LT1 EFI marine setups back in the day...

.. Intake OP mentioned may have the 1-fuel-line system regulator/bypass at the pump/tank for safety in a boat... TPS is just the same contraption as the volume control in radios, TVs, ect. for past 100 years... repackaged for automotive use and price raised several times... something else can usually be adapted...

fireburdluvr85

well brother of mine, seeing as ive now seen this thing it is definitely unique. definitely for a sbc. only worried that the iac has no mounting. gonna help my brother explain this as im alittle more engine literate if u will, he will be running the 411 pcm with this "tpi" intake. the engine in question will also have a procharger. it looks like a raised 4" lt1 intake but with a cast throttle body. my only major concerns are that there are no iac,egr mounts. the tps can use a mid 90s truck one. we came up with the idea of cutting off the "cast" throttle body and have a plate welded on to mount a ls series throttle body therefore utilizing the iac, tps. still stuck on the egr tho? any body know of a remote mounting for the egr?

BuzzLOL

.. I seem to recall some GM V6's having a remote mount EGR setup... on Buick GN's?

TTOP350

iTrader: (8)

Post a pic or a link to pix of this intake if you would..

fireburdluvr85

a link may not happen. i looked for almost 2 hrs and honestly gave up. doesnt seem like much time but have a 2 yr old running around. ill try to snap some pics next time i see it. if anybody cares to look it up.... 87-89 mercruiser 375hp intake manifold. used in cigar boats and speed boats of that era. not many left as only 500 were produced and most were salt water use.

snake70

Been a few months mainly due to some issues with a machinist. I have pics. I need the front of the.plenum cut off yes iac is needed and there is no provision for it. So i orderd a 92 mm ls2 throttle body and getting a spacer fabed up to weld to the plenum i have a egr set up i like of a mid 90's buick v6. So far so good just got burned by a machinist who had my parts for 3 months and did nothing with them

snake70

Dum question but how do i load pics? Its been a long time like 7 yrs. Since i did it last

Street Lethal

iTrader: (16)

Does it resemble the big block one...?

snake70

Not at all i mean first off i have been working on engines for 10 yrs. I know the difference between a sbc.and. bbc second its part of the casting on top that says 5.7 efi mercruiser 3rd u was sold countless books and articles on this intake straight from a mercruiser tech. I just having trouble uploading them

Street Lethal

iTrader: (16)

Relax, I didn't question your "credibility", I asked a simple question if they looked alike...

snake70

its just i have been asked this already.

snake70

it worked!!!!!!

snake70

excellent

snake70

got it now

snake70

tiny pictures, i just cant win

snake70

I have the 411 pcm from a 2001 gmc van i have the harness from the same van i have the sensors etc. I still need to convert the 4l60e to match my cable spedo and i have the baffle gas tank issue still. And 400 sbc is eternally balanced the.the.balancer needs machining to fit the.reluctor wheel.

vetteoz

iTrader: (13)

Pics are fine
Just right click on them and select "open in new tab"
Will open full size

snake70

Good. I am hope to document this.build the best i can and i want everyone to this this intake

Orr89RocZ

iTrader: (20)

Looks good. I've seen this intake for sale a few times..think you can still get some of the bases but no plenums. Not sure what fuel injector rails fit it. or what TB's were used. I figured some sort of GM type but I guess now. I wanted to try running one with a custom fabbed plenum for my boost project but I'm sticking with the single plane efi for now

Smart idea to go LS throttle body. Best bang for the buck and you could use it with TPI electronics if you wanted to but the 411 offers more support for tuning around most places in the US

Abubaca

iTrader: (3)

That's pretty cool. ....I'm gonna follow along I think.

snake70

Im gonna post some pics of the intercooler soon and the car its all going into. Its going on a 79 trans am. I know not a thirdgen but the guys over on those forums i don't trust with info and help and this is usually the.place i turn to.

Orr89RocZ

iTrader: (20)

This is one of the best sites for EFI SBC's around.

bluegrassz

iTrader: (3)

Interesting build.

snake70

Yes the fuel rails may be an issue. I need to change them up a bit i want to use the rails them selves but replace the hard lines and fittings. The fittings straight into the rails seem to be locktighted in though. Also what size injector would work best with a boosted 400 sbc at say 10 lbs of boost. In sure the stock 30 lbs won't do well.

snake70

And as far the egr i am routing it like i saw on the northstar engines and mid 90's buick v6 from the exhaust manifold to a plate fitting the standard egr mounts to then into the spacer that the throttle body will mount to, i am assuming that if gm spent alot on r/d on that setup and it is on millions of cars it must work. Of course though the metal egr lines need to be extended so i cam up with an idea, metal gas line for your standard dryer or oven same diameter and about the same thickness and looks the same. Any thoughts or advise on my choices?

Orr89RocZ

iTrader: (20)

What heads/cam on the thing? What method of boost? Blower/turbo? From that we can get an estimated hp goal and go from there. But a half decent 400 on 10lbs will make 500whp. Decent build will make 600-650whp. Better build will make 700+ All depends. My setup was AFR 195 heads and a medium sized 233 deg hyd roller, .564" lift. Thats a decent build imo, not overly huge on heads/cam, somewhat mild. My car did 640 on 12lbs but that was a very low reading mustang dyno in our area...likely closer to 700-720 whp on a typical dyno jet.. We've seen 70whp difference from that mustang dyno to a dyno jet on same day with a heads/cam ls1 car that made 400's whp. What makes me sick is some supra made over 1000whp thru a th400 on that darn mustang dyno.... ewwww

snake70

Now this will get you going the heads are 65 cc STOCK sbc heads that have been gone through to flow better 230 on the intake and 170 fourth exhaust 1.6 shaft mounted roller rockers the block is a 2 bolt splayed to 4 bolt are bolts everywhere 6.0 rods Keith black pistons 30 over shop says 11.5 compression and i want to drop it to 10.5 so i may need a thicker head gasket i know boost doesn't like high compression and its. V1 vortech procharger.

Orr89RocZ

iTrader: (20)

Iron head? I doubt you will get anywhere near 10 psi on that compression on pump gas. Doubt you can drop it down far enough with a head gasket swap. It have to be around 9 to 1 to have a chance with some boost on pump 93 gas

snake70

Yep iron head, i read that a intercooler would help cool the intake charge to make up a bit with the higher compression. Am i wrong?

Orr89RocZ

iTrader: (20)

It helps but only so much it can do. Still think you are way high on compression at anything over 9.7 to one

snake70

Again advise for a novice helps. I really want to use these heads but i could locate another set sounds like a 70 cc might be needed? Never was one for forced air induction but i got a good deal on a used setup and want to see what all the fuss is about

Orr89RocZ

iTrader: (20)

70cc would help abit but still be high on comp with an iron head. Find out what pistons you have. Typical flat tops are about -5cc of valve relief which with a 65cc head, you'd get 11.4 to 1 compression or so. 70cc would give 10.7 to 1. I'd like to see 9.5 to 1 max with iron head and few pounds of boost on pump gas. May need alot of meth to help. Depending on the setup. Aluminum heads are much better for heat discipation and could possibly tolerate 9.5-10 to 1 compression range better.

You really want a dished piston for that 400 to get comp down

JensenBlayloc

It looks awesome. Does it run on MAF or Speed Density? Is the sensor compatible with the standard ECUs?

Jeffs82TA

iTrader: (1)

Isn't that just basically a edelbrock 70 (something) tunnelram designed for mercruiser efi applications? Looks a lot like one but they are designed for like 5000rpm to infinity, wonder how that would work in a street application since high rpms are boat territory.

Cool intake though good luck with your build

snake70

Its is going to run the 411 pcm using a ls2 aftermarket throttle body which is a maf. And yes it does resemble a tunnel ram setup but i don't know about 5 k to infinity. Sounds like this engine needs a lot of help getting this.compression lowerd, dam i got this thing for a steal to.11.5 is a far way from 9.5 this was a impulse by i got it brand new for 2k from a shop when a customer bought it they never picked it up for over a yr. So they sold it again! To be honest i was told i would be fine with just an intercooler, but that's coming from a honda guy who throws turbos on anything. 9.5 huh, is that pretty much a stock number? I don't want to have to a different engine for this build so any correct info or advice is greatly appreciated.

Orr89RocZ

iTrader: (20)

Carbs may tolerate more compression with intercooler but 11-11.5 is HIGH with iron heads. E85 would have a better shot at it with an intercooler.

9.5 with iron is a good number for mild boost. 8's is better for higher boost. Aluminum heads 9-9.5 is good for most boost numbers you'll run on pump gas. 9.5-10 to 1 is ok for mild boost levels. Again alot of factors go into this but this is a guideline

I'd just leave it 11.5 to 1 and skip the boost and just spray it, but its gonna need a big cam to have a chance on pump gas either way

snake70

I don't mind changing the heads and adding a thicker head gasket. The shortblock is solid and i want to use it. I also want the procharger. Would you advise in your opinion a 70 cc or bigger head with a thick gasket. I will also be asking a couple of local shops on how to drop this compression. I saved a ton on this engine so i have a good budget for new heads. How about 76 cc heads? A quick search on the local craigslist showd a set of aluminum 76 cc 190 heads for a fair price

Orr89RocZ

iTrader: (20)

If you can spend the coin, get aluminums in a 75-76cc chamber and a try a .050" gasket if the block is zero decked (piston tops are flush with block deck surface) That will give you 10 to 1 which is ok for few pounds of boost. Meth injection and intercooling will definately help get 10-12 psi out of it.

JensenBlayloc

You have to keep in mind boost adds to effective compression, and that complicates tune, fuel, and knock issues. So that is why 8.5 to 9.5 is really the sweet spot for mildly boosted street applcations.

snake70

So at 10.1 i would only want a 10 psi max good that id what i want to hear i could always go with a small boost number like 8 psi, i am assuming with what i am learning here that the more boost i run the lower compression is needed. Now my plans are for only 600 whp nothing crazy. And manly want this supercharger for show and sound. My car goes to shows and i think it will get slot of looks with this intake and procharger. But if the occasional stang or 4 banger crowed Me id like to take off

Orr89RocZ

iTrader: (20)

10psi with a 10 to 1 motor with good heads and cam should get you 600whp at 400"...but you start testing the block strength at that level Whole nother can of worms

My baby 401 did 640 on 12psi on a very stingy mustang dyno....dynojet it may have been 700whp. When I say stingy (and i know most say this about dynos when they dyno low ), I mean a heads cam ls1 car dyno'd 70whp different between that mustang dyno and a shop's dynojet down the road about 1 hr away on the same day, same tune

snake70

So i will go this weekend and and get those aluminum heads. I hope i can get something for these stock heads they flow massively and have 1.6 shaft mounted rockers.

snake70

Good head issue solved, compression solved. Next issue i want to use this setup from the van i took every wire and sensor from this van i just want to run the engine and trans with it . I have the knock,temp,maf, timing chain sensor with reluctor wheel. Is there any other sensor that i need? And is there a larger maf that i can use? My throttle body is 4" and my intercooler piping is 3.5 but the maf looks like its a lot smaller.

snake70

I am looking at the routing for vacuum on my tpi intake i have and i am hoping that it will work properly run in the same location on this mercrusier intake

snake70

Vacuum locations have been provided as well as a wiring diagram to rum my 89 gay dual fan setup. You guys are fasttracking this build!!!!

TT 68

Very cool intake design. Too bad there aren't more of them around.

Under the plenum top looks a whole lot like an Edelbrock street tunnel ram intake base does just with injector bungs added.

Add on a custom upper plenum for a common throttle body and you are there.

Twin_Turbo

iTrader: (25)

The base is an edelbrock victor ram. I stupidly passed up the opportunity to buy a prototype of that manifold in the UK year ago, it was almost identical but without the mercruiser scripts on it and the top was smooth and completely bare with a goldish hue. I know of 1 other guy who has the same manifold.

The later magnum 350 EFI mercruisers had a different manifold top the bottom was the same but I think those came w/ a removable TB.

Snake want to sell it???

BuzzLOL

.. That manifold looks like what I've been planning to do with my '87 GTA... put an injector bossed tunnel ram base under my TPI plenum/throttle body...