Formula_272_SR1

Thinking about repowering my 272 this winter and like to get a few thoughts from the more experienced formula guys. Ive only had my Formula for a little over a year and had a great summer with It!

However, it's clear the old reliable 5.7's 260's are tired. My goal is to hit the low 70's which I really see as the upper limit for the Alphas. If the information I gathered is correct, this was a 60mph boat from the factory with the 260's. My current best is 55...... I realize Bravos would hold up better behind 300+ hp but I just replaced both drives at the beginning of the season and converting them just isn't in the budget. Im leaning towards doing a budget build using vortec heads to achieve a honest 350hp per side. If I'm calculating the variables correctly, it appears 700ish hp will get the job done. Anybody have any similar experiences to share? Any low budget build small block recipes out there?

79formula

I used my stock 79 block, crank, and rods. I bored .030 over, used speed pro coated pistons, flat tops with 4 valve reliefs. The shortblock was assembled with all new bearings and seals. I put in a comp cam ( COMP Cams#249-12-236-3
Xtreme Marine Hydraulic Flat Tappet Camshaft
Chevy Small Block 262-400ci 1955-98
Lift: .462"/.477"
Duration: 262°/268°
Lobe Separation Angle: 112°
RPM Range: 1300-5500)

I then used a set of reconditioned vortec heads that I got from a local machine shop for $250. The intake is a edelbrock Performer RPM Air Gap with a 1409 Edelbrock carb. The spent gases exit the engine via GLM center rise manifolds and 4 inch Hardin through hull tips.

I dont know the actual hp but based on the half dozen or so Vortec write ups in hot rod mags on similar builds, I would guess 400-410 hp @5600 with car headers. I would think its an honest 370-380hp as it sits in the bilge. HP numbers dont matter anyways, what does matter is I gained 12mph. I went from 54 to 66. The boat is a rocket at any speed on plane. Its kinda scary (18ft).

79formula

I spent about $2000 on all the parts and machine work to button up the longblock.

Formula_272_SR1

That was a great deal on the reconditioned heads. Thanks for the info, your cam selection is also very close to what I had in mind......your budget is very similar to mine at about 2k per engine. I'm hoping get this done for 5k total. I'll have to shop around hard unless I get lucky and score a good deal on a set of long blocks.

79formula

If i could do it again I would have went bigger on the cam. It idles like stock. You cant even tell its cammed. The price to rebuild included pressing in a new sleeve in the number one cylinder. If you didnt have major component failure, you could get away with re using pistons, hone it, and put new rings on. That would save 200-300 per side.

t500hps

A buddy had a 272 years ago with the 454/330hp motors. He did a few things for more power and he claimed the HP was upped to 400 (none of us felt it was that high and I can't remember what he did now)......boat hit 70-71 on a good day, with the tide and wind at his back.

Formula_272_SR1

If the big block numbers were able to achieve the 70 mark, I think the small block setup will actually be a benefit due to the weight savings and similar output. I'd guess a 500 lb weight reduction on the stern.

79formula

food for thought, mercurys current 330hp 7.4 repower option is a vortec 325hp small block.

sprink58

You may have read what I did with my 255 which is kind of where you are headed. Shop hard and you can get a marine long block 355 with Vortec heads and Roller Cam for around $2500-$3000 each.I am running the Comp Roller Extreme Marine 272 with Comp Roller Rockers and heavy valve springs.I also chose to use oil coolers which in your cooler water might be an overkill. Re-use all of your externals and you can do it yourself for between $5000-$6000. If you are running in fresh water and your exhaust is decent you can get away with re-using for a while. If you are running in salt like me add $500/engine for new OEM Mercury Cast Iron exhaust manifolds and risers. The new or re-man long block is a better bang for the buck unless you have access to a machine shop and can get everything done on the cheap. These motors will give you a reliable 800-850 total Horsepower in the water which will push your 272 into the low to mid 70's. To get there you will need a pair of 23" Mirage plus props and you will be spinning those SBC's at 5000-5500 RPM.

The Alpha's will live for short burst at those speeds. Don't do hole shots and do get a pair of drive showers. Save up for the Bravo swap so you can go run it with out "sucking up the seat covers" every time you nail it.LOL I do highly recommend the lager Bravo couplers that will bolt up to your flywheels. The Bravo and Alpha bell housings are the same.

Our hulls really like the lighter twin SBC's in the rear with 23" Mirage Plus props. I am getting about 7% prop slip with mine...2000 RPM is 35 MPH GPS and 5250 RPM is 75 plus depending on trim.

Formula_272_SR1

Thanks sprink.....I did see some of the information on your repower. You are correct, I'm leaning towards the direction you did without the Bravo conversion. I would imagine you are very pleased with your setup and the Bravo's must have been the perfect finishing touch for durability and handling.

Fortunately, I already have the mirage 23's. I believe this is the factory setup? I was also fortunate and found a great foundation to work with. While the boat had a lot of deferred maintenance when it arrived, it was a relatively low hour boat that was in the same family since new. You all know the story, in the final years of ownership, the previous owner began to loose interest and the boat started to get neglected.

I got stacks of receipts for work done over the years including a transom rebuild which we all know is the largest concern with our old formulas. Why they did such a great job building this boat and then did poor glass work in the stern is so unfortunate......anyway, The real challenge for me would be finding a similar deal like you did on the short blocks. It would be great to source and build the engines over the winter layup and then just drop the new engines in the spring.