Fasteddi sbc to merlin 509 swap
 

Well my sbc 2 bolt main engine blew yesterday. Made a few good passes before hand with a best of 10.63@126mph. So I'm desperate to get another engine running and in this week.

A close friend had a merlin 509 550hp 575tq engine that I can toss in as soon as tonight if itll fit. I personally rebuilt this motor for him last year.

I'll post more as time come along but who has swapped a big block in? I know headers are tough to fit. But how about motor mounts? Sbc and bbc are the same? Do I need to knotch anything to make the engine fit. I'll continue to do some research ..

Re: Fasteddi sbc to merlin 509 swap
 

Our experience with a crate 502 was simple enough. Chassis was an 86 TA with a TKO 500.
Headers were Super Comps which pushes the collector out towards the rocker panels. I didn't much care for the result and would think that something else has come along in the nearly 20 years since the swap. A remote oil filter was used along with an oil cooler. That was mounted under the cover in front of the rad. There was also an issue with the valve cover and wiper motor. Its been so long though that I don't recall what the solution was. The particular car has been in storage since shortly after the swap and never did get sorted out.

Re: Fasteddi sbc to merlin 509 swap
 

The engine will drop in on the sbc mounts. Had one sitting in my engine bay for a decade.

Re: Fasteddi sbc to merlin 509 swap
 

What headers did you use? I'm assuming I need 2 inch or better primary's for a 550hp bbc?

Re: Fasteddi sbc to merlin 509 swap
 

Dang, sorry to hear that Mark! Goodluck with the big block swap, I'm sure you will get it done.

Re: Fasteddi sbc to merlin 509 swap
 

Cant comment on what headers work but 1 7/8 will work for a 502 550hp just fine. If you put a more serious cam and head situation on, 650+ hp can be made and 2" would be better

It be alot easier to fit stuff if you motor plated it and remote mounted oil filter

I got 2 1/8 to fit pretty well so far although still tweaking passenger side but i have motor plates

Re: Fasteddi sbc to merlin 509 swap
 

Thanks bud. I'm good at pushing the limits of stuff.. lol v6 to sbc to bbc now. I dont think I can go wrong with a merlin ii block, forged crank, pistons, and h beam rods next step 9 second car now with some help to the merlin engine.

Re: Fasteddi sbc to merlin 509 swap
 

I do have a remote mount oil filter with that motor so that should help. As for a motor plate... I dont know where to start for that


https://cimg9.ibsrv.net/gimg/www.thi...edd87332c4.jpg
Some carnage

Re: Fasteddi sbc to merlin 509 swap
 

I had a custom tri-y header with 2-1/8 primaries made by Lemons specifically to fit 3rd gen and route exhaust down the tranny tunnel.

Most people use Hooker swap headers but the collectors end up out by the rocker panels.

Re: Fasteddi sbc to merlin 509 swap
 

That was my experience with the headers. It makes for a mess with the rest of the exhaust.

Re: Fasteddi sbc to merlin 509 swap
 

Just got it home. Tis a big motor https://cimg4.ibsrv.net/gimg/www.thi...644f0a9c4d.jpg
https://cimg7.ibsrv.net/gimg/www.thi...c82777a181.jpg
https://cimg8.ibsrv.net/gimg/www.thi...df8343f073.jpg

Re: Fasteddi sbc to merlin 509 swap
 

I hope you don't need windshield wipers!

Re: Fasteddi sbc to merlin 509 swap
 

Following....

Re: Fasteddi sbc to merlin 509 swap
 

9.80" or 10.20" deck height? Seems to be a lot of conflicting info online.

Re: Fasteddi sbc to merlin 509 swap
 

Sorry about the 383.
It looks like you are going to have to reconfigure EVERYTHING to get that big block to work.
I would try to stay SBC, just go bigger and stronger. You still have the heads and entire top end.

This is still the best thread on thirdgen.org!

Re: Fasteddi sbc to merlin 509 swap
 

Ha dont worrie I dont them anyways. They have been removed for a few.years now.

also the deck on this motor is 9.8 which is stock height I believe. The exhaust is the only thing thats going to be a pain. Else then it's a tight fit. It should slip right in and bolt up to the trans and motor mounts.

Re: Fasteddi sbc to merlin 509 swap
 

My tall deck fit fine?

Re: Fasteddi sbc to merlin 509 swap
 

No interference with the wiper motor assembly? At a minimum we had to use the low profile cast factory valve covers and still had to fiddle with the wipers.
This is with OEM engine mounts.

Re: Fasteddi sbc to merlin 509 swap
 

I dimpled the valve cover and trimmed some of the plastic off the motor cover but it clears

Re: Fasteddi sbc to merlin 509 swap
 

Damn that is a beast. What trans are you bolting up to it?

Re: Fasteddi sbc to merlin 509 swap
 

Bolting to a custom hughes th350 with a transbrake. Rated at 800hp. Worked well behind the wild 550hp sbc. I contacted ptc about my custom 8 inch converter. They said that it should stall at 5200rpm behind that big block. And shift at 6200-6500. The 509 peaks up at 5900rpm so hopefully we are ok. They say its good enough for 600-650tq... the merlin is 585 tq as it sits if I dont play with it so hopefully they are right. I'm guessing 11 flat or a touch over with this 540hp 585tq bov block. I ran 1.47 60 foots with the small block. I'm hoping for 1.50s with the heavy big block. Merlin 509 weights 650lbs they say

Re: Fasteddi sbc to merlin 509 swap
 

Thats alot of stall speed for a 5900 rpm peak

Re: Fasteddi sbc to merlin 509 swap
 

I know it worries me. Peak rpm on my last motor was about the same. Shift 500rpm over peak is 6400. So a gap of 1200 rpm.. which is ok for drag only but That's alot ot rev for a big block even if it is bulletproof. I wana put a roller solid in it badly. And new alum heads but that I'm sure will push it up to 700hp which requires me to upgrade some things....

Re: Fasteddi sbc to merlin 509 swap
 

Idk what specific internals are in it but 6500 isnt alot for most bbc lol

Re: Fasteddi sbc to merlin 509 swap
 

The guts are:
Mahle coated Manley 12cc dome forged pistons
Eagle 4340 forged crank
Eagle forged H besm rods 4340 with l-19 bolts
Merlin ii iron block. 4 bolt main with priority oiling, blind taps, and some other things. 4.5x4.0 bore and stroke

I would think this would be safe to take to 6500 all day long if not 7000 all day when I have a bigger cam. This one I have is basically the same as the xr288hr I had in the small block. Same durration exc. This one now just has some more lift

Re: Fasteddi sbc to merlin 509 swap
 

Hell yeah that will go 7500-8000

Re: Fasteddi sbc to merlin 509 swap
 

Carnage... looks like it was the rod ot the crank. Mabey spun a bearing and that's what made the rod take it exit? They were those 51xx forged eagle rods and eagle bolts. https://cimg3.ibsrv.net/gimg/www.thi...887549f324.jpg
https://cimg4.ibsrv.net/gimg/www.thi...3ebf6cfe1b.jpg
https://cimg5.ibsrv.net/gimg/www.thi...aacf4afc43.jpg
https://cimg6.ibsrv.net/gimg/www.thi...43d73256f1.jpg
https://cimg7.ibsrv.net/gimg/www.thi...57cd6e5c43.jpg
https://cimg8.ibsrv.net/gimg/www.thi...5641596fac.jpg
https://cimg9.ibsrv.net/gimg/www.thi...b34bedb551.jpg

Re: Fasteddi sbc to merlin 509 swap
 

Eagle perhaps?

Re: Fasteddi sbc to merlin 509 swap
 

I think those rods were overpowered. The 5140 rods arent great. The forged h beams are awesome for the money tho

Re: Fasteddi sbc to merlin 509 swap
 

Wow that went boom good. At least the heads can be used on the next project

Re: Fasteddi sbc to merlin 509 swap
 

Undoubtedly. And maybe the 2 bolt main block...

Re: Fasteddi sbc to merlin 509 swap
 

Starting to make headers tommorow. This is a bracket car now. Front fender headers. Tight fit but the bbc bolted all up like a champ. Easy. https://cimg1.ibsrv.net/gimg/www.thi...7d03c67271.jpg
https://cimg2.ibsrv.net/gimg/www.thi...9cbd69631c.jpg
https://cimg1.ibsrv.net/gimg/www.thi...d5646a1274.jpg
https://cimg3.ibsrv.net/gimg/www.thi...81ebaafca5.jpg

Re: Fasteddi sbc to merlin 509 swap
 

Perhaps I'm too much old school but I still like the BBC.
I've been trying to finagle the 502 out of the Firebird for years now but the "owner" (despite what he owes me in terms of storage ) is too rich to give a crap about his nice Firebird and drive train slowly returning to the earth.
Looks good Eddi. Waiting for results. Then I can really rub the Bird's owner's face in it. He gave up as the car was unmanageable at the strip given his car "formula" (all street, no suspension).
I have no doubt whatsoever that you'll make it happen.

Re: Fasteddi sbc to merlin 509 swap
 

Stock K member? Any notches? Did you have to swap oil pans?
Looking good. And the story continues.......

https://i2.wp.com/gruntworkpodcast.c...?fit=625%2C479

MORE POWER

Re: Fasteddi sbc to merlin 509 swap
 

Stock k member. No notches. It had a 8 qt pan on it for a chevelle. Fit right into sbc motormounts. No issues at all.

Re: Fasteddi sbc to merlin 509 swap
 

Header parts will be here today. 2 inch kit with slip on collectors 2x3.5, weld up tubing kit, bbc flanges, new header bolts. I'll reduce down to 3 inch stainless and hopefully run it out the fender. Pure race car now. A 509bbc with fender exits is going to be loud.

my 2 month old baby has spent more time in the garage then most teenagers...lolhttps://cimg4.ibsrv.net/gimg/www.thi...4f62472d8a.jpg

Re: Fasteddi sbc to merlin 509 swap
 

https://cimg5.ibsrv.net/gimg/www.thi...7e97280387.jpg
Let the fun begin!

Re: Fasteddi sbc to merlin 509 swap
 

I love this forum.

Yesterday read a three year old thread with people arguing back and forth about forced induction options, OP still hasn't gotten anywhere.

And here's Eddie, with a Big block in his car within a week of blowing it up.

Not trying to bash anybody, just love the variety around here.

Re: Fasteddi sbc to merlin 509 swap
 

Motor swap looks good. Cute kid too.

Re: Fasteddi sbc to merlin 509 swap
 

haha yea its wild at times on here. If you know me, you know that stuff happens and I've went from a 140hp v6 to a 300hp turbo v6 to a 400hp turbo v6 to a 500hp sbc and now a 550hp bbc. Ever changing but this puppy is built to take the power.

Finally got some good specs on the motor.
A very mild 509 merlin ii cnc cast iron 4 bolt block.
Crane 296-2 cam (236/246) under .600 lift. 9.5:1 compression. Je forged pistons, Manley forged h beam rods, eagle 4340 forged crank. Grumpy Jenkins heads (345cc intake runner 2.30 valve) Merlin single plain intake, holley 850 with proform intake. S60 4.10 gear, ptc custom 5k converter, th350 with a brake, race weight 3420lbs in the process of building headers at the moment.


Thanks! Tool me only 2 hrs to swap in motor and hook everything up. It's going to take me 20 hrs to build headers.... but itll be worth it. Everytime I go in the garage she is there with my. Teach them young!

Re: Fasteddi sbc to merlin 509 swap
 

That sounds like it should make alot more than 550 hp. 345 cc heads should flow decent. Thats a good sized head for a 509, on the big side. If they are like the darts, 650 hp is common with hyd rollers of that size but over .600” lift.

There’s definitely potential in that setup

Re: Fasteddi sbc to merlin 509 swap
 

When I first saw the title of the thread I thought here we go another dead end. So happy to see it was fasteddi knowing it would actually be done and right.

Re: Fasteddi sbc to merlin 509 swap
 

That's great. That never worked very good with my daughter. She never liked to be put down if she was awake. Then by the time my son was born, I had two and that didn't work! But now they are starting to help me more and more.

Re: Fasteddi sbc to merlin 509 swap
 

Lol quite a few of those type threads in the PA section

Re: Fasteddi sbc to merlin 509 swap
 

Was there damage to the vehicle? underhood area, hood? Did the piston stay in the bore?

Re: Fasteddi sbc to merlin 509 swap
 

Pistons stayed in the bored. So no damage else then the engine


I'm always committed to a build lol I'll admit in addicted to building up race cars and racing... seriously.


these heads supposedly flow 366cfm at .600 lift. Almost 400cfm at .700 do else then they weight a million lbs they seem to be good. A big solid roller, I think would make this a 650hp engine quite easy.. and with a 950cfm+ carb.

Re: Fasteddi sbc to merlin 509 swap
 

The guys on chevelle forums do alot of bbc hyd roller stuff and 600+ is common with 468-496’s let alone the 509-540 stuff. Alot of them are closer to 10-11:1

Re: Fasteddi sbc to merlin 509 swap
 

If I go a notch smaller on my compression chambers and get my quench at .040 my comp will be up to 10.0:1 which will help. A nice roller is definitly in the mix soon.

Re: Fasteddi sbc to merlin 509 swap
 

Yeah it definitely can be improved. Even similar duration but tighter lsa and mid high .600’s would pick up

Re: Fasteddi sbc to merlin 509 swap
 

Headers are going ok so far. Going to be exiting out where the batt was at before. 2 inch primary's 2 1/2 hrs in so far. Some heat wrap and these puppy's will work out great.

slip on collector and single flanges.
https://cimg3.ibsrv.net/gimg/www.thi...103e9bcafd.jpg
https://cimg5.ibsrv.net/gimg/www.thi...1a6cd95da0.jpg